def index
      raise CanCan::AccessDenied.new unless current_user
      @scratches = ImageScratch.where(ownable: current_user).all
      (authorize! :read, @scratches[0]) unless @scratches.empty?
    end
def index
      raise CanCan::AccessDenied.new unless current_user
      @scratches = ImageScratch.where(ownable: current_user).all
      (authorize! :read, @scratches[0]) unless @scratches.empty?
    end
GET /image_scratches