Your project looks very promising. I'm not sure if this feature doesn't exist or I cannot find it anywhere on demo account, but: what's missing for me is fine grained ACL/permissions management.

In our company we are using https://www.bookstackapp.com/ as knowledge base solution for multiple clients/projects (separate installation for each). Main requirement is to be able to control which user or group can access particular document or group of documents. Is it possible to achieve something like this using your project?