1  def Model
   2  
   3    @@versioned_columns = [:title, :body, :rendered_body, :user_id]  
   4    acts_as_versioned :if_changed => @@versioned_columns
   5  
   6    def self.non_versioned_columns
   7        self.class.columns.collect(&:name) - @@versioned_columns
   8    end
   9  end