diff --git a/lecture_5/homework/.rspec b/lecture_5/homework/.rspec
new file mode 100644
index 00000000..c99d2e73
--- /dev/null
+++ b/lecture_5/homework/.rspec
@@ -0,0 +1 @@
+--require spec_helper
diff --git a/lecture_5/homework/Gemfile b/lecture_5/homework/Gemfile
index f10bbf07..51662319 100644
--- a/lecture_5/homework/Gemfile
+++ b/lecture_5/homework/Gemfile
@@ -3,7 +3,7 @@
 source 'https://rubygems.org'
 git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
-ruby '2.6.2'
+ruby '2.5.3'
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.2.2'
@@ -42,6 +42,7 @@ group :development do
   gem 'listen', '>= 3.0.5', '< 3.2'
   # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
   gem 'rubocop', require: false
+  gem 'rubocop-rspec'
   gem 'spring'
   gem 'spring-watcher-listen', '~> 2.0.0'
 end
@@ -50,5 +51,9 @@ group :test do
   gem 'rspec-rails'
 end
 
+group :development, :test do
+  gem 'factory_bot_rails'
+end
+
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem 'tzinfo-data', platforms: %i[mingw mswin x64_mingw jruby]
diff --git a/lecture_5/homework/Gemfile.lock b/lecture_5/homework/Gemfile.lock
index 411593e8..208880eb 100644
--- a/lecture_5/homework/Gemfile.lock
+++ b/lecture_5/homework/Gemfile.lock
@@ -59,7 +59,13 @@ GEM
     crass (1.0.4)
     diff-lcs (1.3)
     erubi (1.8.0)
+    factory_bot (5.0.2)
+      activesupport (>= 4.2.0)
+    factory_bot_rails (5.0.2)
+      factory_bot (~> 5.0.2)
+      railties (>= 4.2.0)
     ffi (1.10.0)
+    ffi (1.10.0-x64-mingw32)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
     i18n (1.6.0)
@@ -83,14 +89,19 @@ GEM
     mini_portile2 (2.4.0)
     minitest (5.11.3)
     msgpack (1.2.9)
+    msgpack (1.2.9-x64-mingw32)
     nio4r (2.3.1)
     nokogiri (1.10.1)
       mini_portile2 (~> 2.4.0)
+    nokogiri (1.10.1-x64-mingw32)
+      mini_portile2 (~> 2.4.0)
     parallel (1.17.0)
     parser (2.6.2.0)
       ast (~> 2.4.0)
     pg (1.1.4)
+    pg (1.1.4-x64-mingw32)
     psych (3.1.0)
+    psych (3.1.0-x64-mingw32)
     puma (3.12.0)
     rack (2.0.6)
     rack-test (1.1.0)
@@ -149,6 +160,8 @@ GEM
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.6)
+    rubocop-rspec (1.32.0)
+      rubocop (>= 0.60.0)
     ruby-progressbar (1.10.0)
     ruby_dep (1.5.0)
     spring (2.0.2)
@@ -167,6 +180,8 @@ GEM
     thread_safe (0.3.6)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
+    tzinfo-data (1.2019.1)
+      tzinfo (>= 1.0.0)
     unicode-display_width (1.5.0)
     websocket-driver (0.7.0)
       websocket-extensions (>= 0.1.0)
@@ -174,23 +189,26 @@ GEM
 
 PLATFORMS
   ruby
+  x64-mingw32
 
 DEPENDENCIES
   active_model_serializers
   bootsnap (>= 1.1.0)
   byebug
+  factory_bot_rails
   listen (>= 3.0.5, < 3.2)
   pg
   puma (~> 3.11)
   rails (~> 5.2.2)
   rspec-rails
   rubocop
+  rubocop-rspec
   spring
   spring-watcher-listen (~> 2.0.0)
   tzinfo-data
 
 RUBY VERSION
-   ruby 2.6.2p47
+   ruby 2.5.3p105
 
 BUNDLED WITH
    2.0.1
diff --git a/lecture_5/homework/app/controllers/buildings_controller.rb b/lecture_5/homework/app/controllers/buildings_controller.rb
index 9b7e9677..e46a59f6 100644
--- a/lecture_5/homework/app/controllers/buildings_controller.rb
+++ b/lecture_5/homework/app/controllers/buildings_controller.rb
@@ -1,7 +1,17 @@
 # frozen_string_literal: true
 
 class BuildingsController < ApplicationController
-  def index; end
+  def index
+    render json: Building.all
+  end
 
-  def show; end
+  def show
+    render json: building, include: 'warrior'
+  end
+
+  private
+
+  def building
+    @building ||= Building.find(params[:id])
+  end
 end
diff --git a/lecture_5/homework/app/controllers/clans/warriors_controller.rb b/lecture_5/homework/app/controllers/clans/warriors_controller.rb
index 6ccf3ff9..9ab1bbff 100644
--- a/lecture_5/homework/app/controllers/clans/warriors_controller.rb
+++ b/lecture_5/homework/app/controllers/clans/warriors_controller.rb
@@ -10,7 +10,7 @@ def index
       warriors = clan.warriors
 
       if params.key?(:alive)
-        if params[:alive].to_i == 0
+        if params[:alive].to_i.zero?
           render json: warriors.dead
         else
           render json: warriors.alive
@@ -47,7 +47,8 @@ def warrior
     end
 
     def warrior_params
-      params.permit(:name, :death_date, :armor_quality, :number_of_battles, :join_date)
+      params.permit(:name, :death_date, :armor_quality,
+                    :number_of_battles, :join_date, :building_id)
     end
   end
 end
diff --git a/lecture_5/homework/app/models/building.rb b/lecture_5/homework/app/models/building.rb
index 23c41918..2d452e0a 100644
--- a/lecture_5/homework/app/models/building.rb
+++ b/lecture_5/homework/app/models/building.rb
@@ -5,4 +5,6 @@ class Building < ApplicationRecord
 
   validates :granary, presence: true,
                       numericality: { greater_than_or_equal_to: 0, only_integer: true }
+  validates :siege_ability, presence: true,
+                            numericality: { greater_than_or_equal_to: 0, only_integer: true }
 end
diff --git a/lecture_5/homework/app/models/warrior.rb b/lecture_5/homework/app/models/warrior.rb
index eacdc13f..b939adc5 100644
--- a/lecture_5/homework/app/models/warrior.rb
+++ b/lecture_5/homework/app/models/warrior.rb
@@ -14,4 +14,11 @@ class Warrior < ApplicationRecord
 
   scope :alive, -> { where('death_date IS NULL') }
   scope :dead, -> { where('death_date IS NOT NULL') }
+
+  after_save :siege_report
+  after_destroy :siege_report
+
+  def siege_report
+    return Reports::SiegeReport.new(building: building).call if building_id
+  end
 end
diff --git a/lecture_5/homework/app/serializers/building_serializer.rb b/lecture_5/homework/app/serializers/building_serializer.rb
index 899c9aa0..e1f1988d 100644
--- a/lecture_5/homework/app/serializers/building_serializer.rb
+++ b/lecture_5/homework/app/serializers/building_serializer.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class BuildingSerializer < ActiveModel::Serializer
-  attributes :name
+  attributes :name, :granary, :siege_ability
 
   has_many :warriors
 end
diff --git a/lecture_5/homework/app/services/reports/siege_report.rb b/lecture_5/homework/app/services/reports/siege_report.rb
index 16a0b3a4..2368f318 100644
--- a/lecture_5/homework/app/services/reports/siege_report.rb
+++ b/lecture_5/homework/app/services/reports/siege_report.rb
@@ -3,10 +3,28 @@
 module Reports
   class SiegeReport
     def initialize(building:)
+      @building = building
+      @warriors = building.warriors
     end
 
     def call
-      raise NotImprementedYet
+      siege = @warriors.present? ? @building.siege_ability = granary_ability : @building.siege_ability = 0
+      @building.save
+      siege
+    end
+
+    private
+
+    def granary_request
+      daily_request = 10
+      samurais = @warriors.where(type: 'Warriors::Samurai').count
+      hussars = @warriors.where(type: 'Warriors::Hussar').count * 2
+      daily_request + samurais + hussars
+    end
+
+    def granary_ability
+      granary = @building.granary
+      granary / granary_request
     end
   end
 end
diff --git a/lecture_5/homework/config/database.yml b/lecture_5/homework/config/database.yml
index 23483946..0a4d7b97 100644
--- a/lecture_5/homework/config/database.yml
+++ b/lecture_5/homework/config/database.yml
@@ -1,7 +1,9 @@
 default: &default
   adapter: postgresql
   encoding: unicode
-  database: rorlevelup2019
+  database: homework_5
+  username: postgres
+  password: Potato
 
 development:
   <<: *default
diff --git a/lecture_5/homework/db/migrate/20190416095847_add_siege_ability_on_building.rb b/lecture_5/homework/db/migrate/20190416095847_add_siege_ability_on_building.rb
new file mode 100644
index 00000000..7c3cf2dc
--- /dev/null
+++ b/lecture_5/homework/db/migrate/20190416095847_add_siege_ability_on_building.rb
@@ -0,0 +1,7 @@
+class AddSiegeAbilityOnBuilding < ActiveRecord::Migration[5.2]
+  def change
+  	add_column :buildings, :siege_ability, :integer, default: 0, null: false
+
+  	Building.find_each { |building| Reports::SiegeReport.new(building: building).call }
+  end
+end
diff --git a/lecture_5/homework/db/schema.rb b/lecture_5/homework/db/schema.rb
index 13f968ab..eaf004e0 100644
--- a/lecture_5/homework/db/schema.rb
+++ b/lecture_5/homework/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_04_05_090544) do
+ActiveRecord::Schema.define(version: 2019_04_16_095847) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -20,6 +20,8 @@
     t.string "type", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.integer "granary", default: 0, null: false
+    t.integer "siege_ability", default: 0, null: false
   end
 
   create_table "clans", force: :cascade do |t|
diff --git a/lecture_5/homework/spec/rails_helper.rb b/lecture_5/homework/spec/rails_helper.rb
new file mode 100644
index 00000000..7331a82a
--- /dev/null
+++ b/lecture_5/homework/spec/rails_helper.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+# This file is copied to spec/ when you run 'rails generate rspec:install'
+require 'spec_helper'
+ENV['RAILS_ENV'] ||= 'test'
+require File.expand_path('../../config/environment', __FILE__)
+# Prevent database truncation if the environment is production
+abort('The Rails environment is running in production mode!') if Rails.env.production?
+require 'rspec/rails'
+require 'support/factory_bot'
+# Add additional requires below this line. Rails is not loaded until this point!
+
+# Requires supporting ruby files with custom matchers and macros, etc, in
+# spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
+# run as spec files by default. This means that files in spec/support that end
+# in _spec.rb will both be required and run as specs, causing the specs to be
+# run twice. It is recommended that you do not name files matching this glob to
+# end with _spec.rb. You can configure this pattern with the --pattern
+# option on the command line or in ~/.rspec, .rspec or `.rspec-local`.
+#
+# The following line is provided for convenience purposes. It has the downside
+# of increasing the boot-up time by auto-requiring all files in the support
+# directory. Alternatively, in the individual `*_spec.rb` files, manually
+# require only the support files necessary.
+#
+# Dir[Rails.root.join('spec', 'support', '**', '*.rb')].each { |f| require f }
+
+# Checks for pending migrations and applies them before tests are run.
+# If you are not using ActiveRecord, you can remove these lines.
+begin
+  ActiveRecord::Migration.maintain_test_schema!
+rescue ActiveRecord::PendingMigrationError => e
+  puts e.to_s.strip
+  exit 1
+end
+RSpec.configure do |config|
+  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
+  config.fixture_path = "#{::Rails.root}/spec/fixtures"
+
+  # If you're not using ActiveRecord, or you'd prefer not to run each of your
+  # examples within a transaction, remove the following line or assign false
+  # instead of true.
+  config.use_transactional_fixtures = true
+
+  # RSpec Rails can automatically mix in different behaviours to your tests
+  # based on their file location, for example enabling you to call `get` and
+  # `post` in specs under `spec/controllers`.
+  #
+  # You can disable this behaviour by removing the line below, and instead
+  # explicitly tag your specs with their type, e.g.:
+  #
+  #     RSpec.describe UsersController, :type => :controller do
+  #       # ...
+  #     end
+  #
+  # The different available types are documented in the features, such as in
+  # https://relishapp.com/rspec/rspec-rails/docs
+  config.infer_spec_type_from_file_location!
+
+  # Filter lines from Rails gems in backtraces.
+  config.filter_rails_from_backtrace!
+  # arbitrary gems may also be filtered via:
+  # config.filter_gems_from_backtrace("gem name")
+end
diff --git a/lecture_5/homework/spec/requests/buildings_spec.rb b/lecture_5/homework/spec/requests/buildings_spec.rb
new file mode 100644
index 00000000..7038ef7f
--- /dev/null
+++ b/lecture_5/homework/spec/requests/buildings_spec.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'Buildings API', type: :request do
+  describe 'GET /buildings' do
+    it 'responds with 200' do
+      get '/buildings'
+      expect(response).to have_http_status(200)
+    end
+  end
+
+  describe 'GET /buildings/:id' do
+    it 'response with 404' do
+      get '/buildings/1'
+      expect(response).to have_http_status(404)
+    end
+  end
+
+  describe 'GET /buildings/:id' do
+    let(:building) { create(:building) }
+
+    it 'response with 200' do
+      get "/buildings/#{building.id}"
+      expect(response).to have_http_status(200)
+    end
+  end
+end
diff --git a/lecture_5/homework/spec/services/reports/siege_report_spec.rb b/lecture_5/homework/spec/services/reports/siege_report_spec.rb
new file mode 100644
index 00000000..1e367228
--- /dev/null
+++ b/lecture_5/homework/spec/services/reports/siege_report_spec.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Reports::SiegeReport, type: :service do
+  subject(:siege_report) { Reports::SiegeReport.new(building: building).call }
+
+  let(:building) { create(:building) }
+
+  describe '#call' do
+    context 'when building without warriors' do
+      it 'returns 0' do
+        expect(siege_report).to eq(0)
+      end
+    end
+  end
+
+  describe '#call' do
+    context 'when building with one samurai' do
+      let(:warrior) { build(:warrior, building: building) }
+
+      it 'returns 18' do
+        warrior.save
+        expect(siege_report).to eq(18)
+      end
+    end
+  end
+
+  describe '#call' do
+    context 'when building with one hussar' do
+      let(:warrior) { build(:warrior, type: warrior_type, building: building) }
+      let(:warrior_type) { 'Warriors::Hussar' }
+
+      it 'returns 16' do
+        warrior.save
+        expect(siege_report).to eq(16)
+      end
+    end
+  end
+
+  describe '#call' do
+    context 'when building with two types of warriors' do
+      let(:warrior1) { build(:warrior, building: building) }
+      let(:warrior2) { build(:warrior, name: hussar_name, type: warrior_type, building: building) }
+      let(:hussar_name) { 'Frog Hussar' }
+      let(:warrior_type) { 'Warriors::Hussar' }
+
+      it 'returns 15' do
+        warrior1.save
+        warrior2.save
+        expect(siege_report).to eq(15)
+      end
+    end
+  end
+end
diff --git a/lecture_5/homework/spec/spec_helper.rb b/lecture_5/homework/spec/spec_helper.rb
new file mode 100644
index 00000000..68b030f2
--- /dev/null
+++ b/lecture_5/homework/spec/spec_helper.rb
@@ -0,0 +1,102 @@
+# frozen_string_literal: true
+
+# This file was generated by the `rails generate rspec:install` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+# The generated `.rspec` file contains `--require spec_helper` which will cause
+# this file to always be loaded, without a need to explicitly require it in any
+# files.
+#
+# Given that it is always loaded, you are encouraged to keep this file as
+# light-weight as possible. Requiring heavyweight dependencies from this file
+# will add to the boot time of your test suite on EVERY test run, even for an
+# individual file that may not need all of that loaded. Instead, consider making
+# a separate helper file that requires the additional dependencies and performs
+# the additional setup, and require it from the spec files that actually need
+# it.
+#
+# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+RSpec.configure do |config|
+  # rspec-expectations config goes here. You can use an alternate
+  # assertion/expectation library such as wrong or the stdlib/minitest
+  # assertions if you prefer.
+  config.expect_with :rspec do |expectations|
+    # This option will default to `true` in RSpec 4. It makes the `description`
+    # and `failure_message` of custom matchers include text for helper methods
+    # defined using `chain`, e.g.:
+    #     be_bigger_than(2).and_smaller_than(4).description
+    #     # => "be bigger than 2 and smaller than 4"
+    # ...rather than:
+    #     # => "be bigger than 2"
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  # rspec-mocks config goes here. You can use an alternate test double
+  # library (such as bogus or mocha) by changing the `mock_with` option here.
+  config.mock_with :rspec do |mocks|
+    # Prevents you from mocking or stubbing a method that does not exist on
+    # a real object. This is generally recommended, and will default to
+    # `true` in RSpec 4.
+    mocks.verify_partial_doubles = true
+  end
+
+  # This option will default to `:apply_to_host_groups` in RSpec 4 (and will
+  # have no way to turn it off -- the option exists only for backwards
+  # compatibility in RSpec 3). It causes shared context metadata to be
+  # inherited by the metadata hash of host groups and examples, rather than
+  # triggering implicit auto-inclusion in groups with matching metadata.
+  config.shared_context_metadata_behavior = :apply_to_host_groups
+
+# The settings below are suggested to provide a good initial experience
+# with RSpec, but feel free to customize to your heart's content.
+=begin
+  # This allows you to limit a spec run to individual examples or groups
+  # you care about by tagging them with `:focus` metadata. When nothing
+  # is tagged with `:focus`, all examples get run. RSpec also provides
+  # aliases for `it`, `describe`, and `context` that include `:focus`
+  # metadata: `fit`, `fdescribe` and `fcontext`, respectively.
+  config.filter_run_when_matching :focus
+
+  # Allows RSpec to persist some state between runs in order to support
+  # the `--only-failures` and `--next-failure` CLI options. We recommend
+  # you configure your source control system to ignore this file.
+  config.example_status_persistence_file_path = "spec/examples.txt"
+
+  # Limits the available syntax to the non-monkey patched syntax that is
+  # recommended. For more details, see:
+  #   - http://rspec.info/blog/2012/06/rspecs-new-expectation-syntax/
+  #   - http://www.teaisaweso.me/blog/2013/05/27/rspecs-new-message-expectation-syntax/
+  #   - http://rspec.info/blog/2014/05/notable-changes-in-rspec-3/#zero-monkey-patching-mode
+  config.disable_monkey_patching!
+
+  # This setting enables warnings. It's recommended, but in some cases may
+  # be too noisy due to issues in dependencies.
+  config.warnings = true
+
+  # Many RSpec users commonly either run the entire suite or an individual
+  # file, and it's useful to allow more verbose output when running an
+  # individual spec file.
+  if config.files_to_run.one?
+    # Use the documentation formatter for detailed output,
+    # unless a formatter has already been configured
+    # (e.g. via a command-line flag).
+    config.default_formatter = "doc"
+  end
+
+  # Print the 10 slowest examples and example groups at the
+  # end of the spec run, to help surface which specs are running
+  # particularly slow.
+  config.profile_examples = 10
+
+  # Run specs in random order to surface order dependencies. If you find an
+  # order dependency and want to debug it, you can fix the order by providing
+  # the seed, which is printed after each run.
+  #     --seed 1234
+  config.order = :random
+
+  # Seed global randomization in this process using the `--seed` CLI option.
+  # Setting this allows you to use `--seed` to deterministically reproduce
+  # test failures related to randomization by passing the same `--seed` value
+  # as the one that triggered the failure.
+  Kernel.srand config.seed
+=end
+end
diff --git a/lecture_5/homework/spec/support/factory_bot.rb b/lecture_5/homework/spec/support/factory_bot.rb
new file mode 100644
index 00000000..94cf464c
--- /dev/null
+++ b/lecture_5/homework/spec/support/factory_bot.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+RSpec.configure do |config|
+  config.include FactoryBot::Syntax::Methods
+end
+
+FactoryBot.define do
+  factory :building do
+    name { 'Western Walls' }
+    type { 'Buildings::Walls' }
+    granary { 200 }
+  end
+
+  factory :clan do
+    name { 'Froggy' }
+  end
+
+  factory :warrior do
+    association(:clan)
+    name { 'Frog Samurai' }
+  end
+end