Add file name to ExerciseFile model

- includes migration and schema.rb changes
- also added ExerciseFile#full_file_name as a required helper to concat
  file's base name and extension (filetype)

(#17)

Author: leoselig

app/models/exercise_file.rb

@@ -1,3 +1,8 @@
 class ExerciseFile < ActiveRecord::Base
   belongs_to :exercise
+
+  def full_file_name
+    "#{self.file_name}.#{self.filetype}"
+  end
+
 end

db/migrate/20160213122258_add_file_name_to_exercise_file.rb

@@ -0,0 +1,5 @@
+class AddFileNameToExerciseFile < ActiveRecord::Migration
+  def change
+    add_column :exercise_files, :file_name, :string
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160212110642) do
+ActiveRecord::Schema.define(version: 20160213122258) do
 
   create_table "account_links", force: :cascade do |t|
     t.datetime "created_at",   null: false
@@ -109,6 +109,7 @@
     t.integer  "exercise_id"
     t.datetime "created_at",  null: false
     t.datetime "updated_at",  null: false
+    t.string   "file_name"
   end
 
   add_index "exercise_files", ["exercise_id"], name: "index_exercise_files_on_exercise_id"