annotate models (#2697)

* add annotate to Gemfile

* rails g annotate:install

* configure annotate_models

* add schema info to models

* fix rubocop to add frozen_string_literal

app/models/setting.rb

@@ -1,4 +1,16 @@
 # frozen_string_literal: true
+# == Schema Information
+#
+# Table name: settings
+#
+#  id         :integer          not null, primary key
+#  var        :string           not null
+#  value      :text
+#  thing_type :string
+#  thing_id   :integer
+#  created_at :datetime
+#  updated_at :datetime
+#
 
 class Setting < RailsSettings::Base
   source Rails.root.join('config/settings.yml')