Add rubocop spacing rules

We were following these rules in most places; we just didn't define them
anywhere.

spec/lib/cache_spec.rb

@@ -7,7 +7,7 @@ describe "Cache flow" do
       debate = create(:debate, tag_list: "Good, Bad")
       tag = ActsAsTaggableOn::Tag.find_by(name: "Bad")
 
-      expect{tag.destroy}.to change {debate.reload.cache_key}
+      expect { tag.destroy }.to change { debate.reload.cache_key }
     end
   end