Add rubocop to our build. (#5004)

spec/integrity/common_mark_spec.rb

@@ -7,7 +7,7 @@ describe "CommonMark" do
     SiteSetting.traditional_markdown_linebreaks = true
     SiteSetting.enable_markdown_typographer = false
 
-    html,state,md = nil
+    html, state, md = nil
     failed = 0
 
     File.readlines(Rails.root + 'spec/fixtures/md/spec.txt').each do |line|
@@ -49,7 +49,7 @@ describe "CommonMark" do
           puts md
           puts
         end
-        html,state,md = nil
+        html, state, md = nil
         next
       end
 
@@ -66,7 +66,6 @@ describe "CommonMark" do
         html = (html || String.new) << line
       end
 
-
     end
 
     expect(failed).to eq(0)

spec/integrity/i18n_spec.rb

@@ -36,7 +36,6 @@ def is_yaml_compatible?(english, translated)
   true
 end
 
-
 describe "i18n integrity checks" do
 
   it 'has an i18n key for each Trust Levels' do