Missing migrations

[Stepych]

The same issue as mattes/migrate#237 - applying "missing" migrations: now if it's less or equal to than the version in the database, it is ignored.

[VojtechVitek]

We explicitly prefer to error out if there's any gap in the migrations. If goose skips those migrations right now, it's probably a bug and we should fix that and make it an error.

We don't want to apply any migrations that are out of the sequence number order.

There shouldn't be any "skipped" migration if you version your migrations properly. See https://github.com/pressly/goose#hybrid-versioning for further explanation.