MigrationNames

Reads a migration's version and description out of its name.

The same convention covers both kinds, which is the point: a .sql file and a class carry their identity the same way, so a class never has to be constructed in order to find out what it is. V2__add_indexes.sql and V2__Add_indexes are the same version and the same description, and R__rebuild_views is repeatable either way. The one difference is forced by Kotlin rather than chosen - . cannot appear in a class name, so a class writes V2_1__… where a file may write either.