Thanks for the answer, Richard.

1. the number of users is not the issue - tens, max hundred. They are students of Uni testing the database (deploying, testing, deleting instances according their needs...).

2. Sure,[ template is ready](https://github.com/DoboKostial/archeo_db/blob/master/db/create_db_template.sql) and they will create DBs from template, that is the only reasonable way to do it....

3. I was thinking about foreign data wrappers (having a user table on one database and the other databases will connect to it), but there is one catch - no one guarantees me that one of the students will not delete the original database and I will be without users....

I prefer to put authentication in an independent database (suggestion 1) and prohibit students from entering it. I will solve the synchronization of roles between databases with an [application script](https://github.com/DoboKostial/archeo_db/blob/master/db/synchronize_from_auth_db.py)....