Fix OperationalError under Django 5+

[julianwachholz]

In earlier versions it would raise ProgrammingError.

[jieter]

The tests fail with django.db.utils.NotSupportedError: PostgreSQL 14 or later is required (found 13.13)., we should change the CI config to use a more recent postgres version.
I'll ask you to rebase this PR after I did that.

[jieter]

#122 Is merged, please rebase.

[julianwachholz]

Good idea! Maybe in the future SQLite could also be included in the test matrix?

I rebased this branch and #109

[jieter]

Good idea! Maybe in the future SQLite could also be included in the test matrix?

Nice idea, not sure if we actually support SQLite though, PR welcome!

I rebased this branch and #109

Thanks!

[julianwachholz]

Nice idea, not sure if we actually support SQLite though, PR welcome!

Yes! In fact I made some local changes to be able to run the test suite against it, as it's easier than spinning up a database.

If you're open to it I can also propose some changes to make development on this package a little easier in that regard. E.g. a simple compose.yml that can spin up the required postgres db in a container.

[jieter]

If you're open to it I can also propose some changes to make development on this package a little easier in that regard. E.g. a simple compose.yml that can spin up the required postgres db in a container.

I started work for this package before I was used to using docker compose. I'm glad to merge a simple example to ease development!