Annotations (#327)

* Add annotate gem to the project
* Annotate models, fixtures, factories and model_specs
* Keep annotations only in Models
* Remove unwanted changes in model specs
* Exclude auto_annotate_models from rubocop

app/models/canned_response.rb

@@ -1,3 +1,15 @@
+# == Schema Information
+#
+# Table name: canned_responses
+#
+#  id         :integer          not null, primary key
+#  content    :text
+#  short_code :string
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#  account_id :integer          not null
+#
+
 class CannedResponse < ApplicationRecord
   validates_presence_of :content
   validates_presence_of :short_code