[feature proposal] abort_if_pending_migrations rake task should check for uncopied engine migrations too


Today I updated an engine and missed an essential database migration because I didn’t run “rake railties:install:migrations”. This was not immediately obvious to me and took some time to debug. I’ve become accustomed to the abort_if_pending_migrations task catching these sorts of oversights. However, because it was an engine migration, abort_if_pending_migrations didn’t catch this.

Anyone have issue with this conceptually? If I don’t hear any chatter here, I’ll propose an implementation in a few days or just create a pull request. See https://github.com/rails/rails/blob/master/activerecord/lib/active_record/railties/databases.rake#L163 for current implementation.