Enables RSpec/EmptyLineAfterSubject & fixes all issues

Read more about cop at http://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/EmptyLineAfterSubject

spec/models/abilities/moderator_spec.rb

@@ -3,6 +3,7 @@ require 'cancan/matchers'
 
 describe Abilities::Moderator do
   subject(:ability) { Ability.new(user) }
+
   let(:user) { moderator.user }
   let(:moderator) { create(:moderator) }