# File lib/paper_trail/has_paper_trail.rb, line 49
      def has_paper_trail(options = {})
        options[:on] ||= [:create, :update, :destroy]

        # Wrap the :on option in an array if necessary. This allows a single
        # symbol to be passed in.
        options[:on] = Array(options[:on])

        setup_model_for_paper_trail(options)

        setup_callbacks_from_options options[:on]
      end