Another option would be to not only store the files on a central server, but also run the applications on that central server and use the Raspberry only as terminal.
Using Edubuntu to turn a normal Intel/AMD computer into the central terminal server is not that difficult, and something even folks that don't know what git is should be able to manage.
Matter of ticking a box during installation, add users to the system, and you are good to go on the central server side.
Not sure how well a Raspberry is suitable for the terminal client side (e.g. I do not know if the USB ethernet controller won't give additional lag, etc.), but it is something I'm going to give a try.