When I was working with migrations and ActiveRecord a couple of years ago, we just treated the production database as authoritative. We basically used migration

When I was working with migrations and ActiveRecord a couple of years ago, we just treated the production database as authoritative. We basically used migrations as disposable chunks of code that would transform the database from state a to state b. If a migration from 3 months ago didn't work anymore it really didn't matter, as the production database was well beyond that point anyway. When we needed to test the migrations, we'd load the most recent backup of the production database into our dev dbs and try it out. But we did have the luxury of running a (fairly small-scale) website rather than distributing an application.