def archive(directory, id, destination_path)
      Dir.chdir(@directory) do
        FileUtils.mkdir_p(File.dirname(destination_path))
        run("git archive --format=tar #{id} -- #{directory} | xz -9e > #{destination_path}")
      end
      destination_path
    end
def archive(directory, id, destination_path)
      Dir.chdir(@directory) do
        FileUtils.mkdir_p(File.dirname(destination_path))
        run("git archive --format=tar #{id} -- #{directory} | xz -9e > #{destination_path}")
      end
      destination_path
    end
archives version id of directory in destination_path