Rails migrations are the ugly stepchild of most projects, even though
actually making them work correctly saves so much time. Even though they seem
like one-off scripts, and also are most of the time when you do need to run them
more than once you are already in a bad place, so be sure that the migration you
wrote, when there was time is not making it worse.
At least doing a quick testing of the rollback is worth your time, in all cases!
So just run
$ rake db:migrate && rake db:rollback && rake db:migrate
When creating a new migration, thank you, you are awesome :).