Feature/81 comments

Completed comment feature using polymorphic attribute.
     -comment actions: create, index.
     -users can comment on different type of activities on: (activities/show path)

Putting this outside everything (non-nested) makes it available on ALL pages across the app. So any div with class "comment" anywhere in the Rails app will have this style applied to it... You should nest it somewhere so it's not "global"