code: def track_changes
        send :include, TrackChanges::CurrentUser
        send :include, TrackChanges::Changes
  
        self.class_eval do
          has_many :audits, :as => :audited
  
          around_update TrackChanges::AroundUpdate
        end
      end
docs: Enables auditing of all changes to an ActiveRecord model. Sets up an
   around filter that will create an Audit for the models <tt>changes</tt>
   attribute.
  
   In addition, this will also define a <tt>attr_accessor</tt> for <tt>current_user</tt>.