def zip
      @zip ||= Zip::OutputStream.write_buffer do |zipfile|
        zipfile.put_next_entry(@filename)
        zipfile.write @data
      end.string
    end
def zip
      @zip ||= Zip::OutputStream.write_buffer do |zipfile|
        zipfile.put_next_entry(@filename)
        zipfile.write @data
      end.string
    end
Public: Initializes the zipper with a filename and the data to
 be zipped.

 filename - The file name of the file *inside* the zip.
 data     - A string with the data to be zipped.
 Public: Zips the file.

 Returns a String with the zipped version of the file.