Issue #4: Update comments

Gemfile

Gemfile.lock

app/controllers/v1/sessions_controller.rb

app/models/achievement.rb

app/models/action.rb

app/models/action_counter.rb

app/models/collection.rb

app/models/collection_item.rb

app/models/complaint.rb

app/models/complaint_reason.rb

app/models/contact.rb

app/models/institution.rb

app/models/item.rb

app/models/learning_object.rb

app/models/package.rb

app/models/progress.rb

app/models/question.rb

app/models/rate.rb

app/models/requirement.rb

app/models/suggestion.rb