Fork it and have it save in localStorage, or POST (ajax or <form>) it to your host site for saving.

One idea could be to bundle it with haste[1] or similar.

[1] https://github.com/seejohnrun/haste-server

It seems to have some kind of filesystem. You can write files, there's /dev, /root, /tmp and /usr, and vimrc and color settings.

Not really sure how it all works, I only took a quick look.