Direct users to newer repository

[lgommans]

Hello!

I would suggest updating the readme to point people to what appears to be a much newer version of this webapplication: https://codeberg.org/intricat/sunders

The good old https://sunders.uber.space only lists this ancient repository as the credited "code base", with no notion that the newer code is available anywhere. Would have saved me some time if I had found this other repository sooner 😅