def write(site_destination_dir)
      if modified?
        Files.copy_p(path, destination(site_destination_dir))
        @is_modified = false
        true
      else
        false
      end
    end
def write(site_destination_dir)
      if modified?
        Files.copy_p(path, destination(site_destination_dir))
        @is_modified = false
        true
      else
        false
      end
    end
allows writing destination only after
 `destination_path_for_markup` has been called