This is definitely better than the traditional rails/django approach to migrations, but the post seems to imply that generating changes against a live DB is a pointless annoyance - I disagree.
If you care about testability - the best way to test your migrations is by testing them directly against the schema they'll actually be applied to.
What if your tool is not the only party making schema changes to the database? What if there was a bug in a previous migration and the database is in a different state than you're assuming? The only way to check for problems like this is to check your actual production state.
If you care about testability - the best way to test your migrations is by testing them directly against the schema they'll actually be applied to.
What if your tool is not the only party making schema changes to the database? What if there was a bug in a previous migration and the database is in a different state than you're assuming? The only way to check for problems like this is to check your actual production state.