(MAINT) Add requirements for acceptance tests

This commit updates the Gemfile with the requirements needed for the
acceptance tests.

It also adds a new entry to .gitignore so that the fixtures directory is
excluded.

Author: chelnak

.fixtures.yml

@@ -0,0 +1,6 @@
+fixtures:
+  repositories:
+    facts: 'https://github.com/puppetlabs/puppetlabs-facts.git'
+    provision: 'https://github.com/puppetlabs/provision.git'
+    puppet_agent: 'https://github.com/puppetlabs/puppetlabs-puppet_agent.git'
+  symlinks: []

.gitignore

@@ -11,3 +11,4 @@ coverage/
 /*.pp
 /tmp/
 .vendor/
+spec/fixtures/

Gemfile

@@ -15,10 +15,18 @@ group :test do
   gem 'simplecov', :require => false if ENV['COVERAGE'] == 'yes'
 end
 
+group :acceptance do
+  gem 'serverspec'
+  gem 'puppetlabs_spec_helper'
+  gem 'puppet_litmus'
+end
+
 group :development do
     gem 'github_changelog_generator', require: false
     gem 'faraday-retry', require: false
     gem 'pry', require: false
+    gem 'pry-byebug', require: false
+    gem 'pry-stack_explorer', require: false
 end
 
 group :rubocop do