GitLab

If a user opens a document already opened by someone else there is a danger that some data might be erased.

This is harder to define than it sounds because some of the document states are updated through the websocket live, we might be able to improve on that to have some form collaborative editing, but it's also possible it would be too much work for too little reward.

Weirdly enough no existing django package use a regular file lock, but I have a module ready from another project if we go that way.