Programmatically undo a migration

[jdrouet]

👋 Hi everyone and thank you for the nice work you do on this crate.
I've been digging a bit in the migration source code and I didn't find anything related to undoing a migration.
I usually use that feature (that I implement myself most of the time) between each of my end to end tests so that the database restarts fresh.
I'd be happy to contribute by adding a undo method similar to the run method found here.
Also, having a parameter to specify the target version would probably be useful ("undo the migration until the version 4" for example).
Would that be interesting?

[jplatte]

This is already supported: https://github.com/launchbadge/sqlx/tree/master/sqlx-cli#reverting-migrations

[jdrouet]

Oh I see, I need the Cli crate to do that, right?

[jplatte]

Yeah, I'm not aware of a (straight-forward) way to undo migrations from within application code.

[jdrouet]

There is one PR that does the job, now it seems complicated to get it reviewed 😅
#1675

[jdrouet]

Considering #1675 has been merged, I'll close this issue