WIP: Fix sandbox not clearing after each test

[jauggy]

Context

If I create a user in test 1, it should be cleared after the test ends and then when I try to create the same user in test 2, it should work. If the sandbox db is not cleared and you try and create a user with a name that already exists, instead it creates a user with random name.

Test Steps

mix test path/to/clear_db_each_test.exs

All tests should pass

TODO

Currently the tests fail and not sure how to fix

https://github.com/beyond-all-reason/teiserver/assets/1305569/4448191a-9b59-45c3-b4f8-0a22e8c806ee

[geekingfrog]

I found the issue and added a fix in https://github.com/beyond-all-reason/teiserver/pull/342 If you want to verify that, you can cherry pick the only commit of this PR (git cherry-pick 8cc544e7eaf7e8e0627611e3d784dc88e08ab63c on this branch) and run this test again.

The problem was that the DB was correctly reset between tests, but the cache wasn't. I don't think my fix is going to solve all cache issues but that's a start.

I don't want to have this PR merged though, since this is merely a test file to reproduce an issue, I think a better place to surface these problem would be a github issue. The code sample was very useful to debug it.

[jauggy]

@geekingfrog did you link the wrong PR?

[geekingfrog]

Oops, yes, I did. I amended my comment and put the correct link in place.