This verison has a worse UI, but also chnages the schema less: One
non-null constraint is removed, but no new columns are added.
Co-Authored-By: Andrea Ciceri <andrea.ciceri@autistici.org>
Co-Authored-By: regnat <rg@regnat.ovh>
By moving the tests subdirectory to t, we gain the ability to run `yath
test` with no arguments from inside `nix develop` in the root of the
the repo.
(`nix develop` is necessary in order to set the proper env vars for
`yath` to find our test libraries.)
