Migrations

@searls In that case you'd be better off `rake db:reset`-ing. (much faster)

In general editing existing migrations is not a good idea: you will be creating extra work for yourself and your co-workers and cause major headaches if the existing version of the migration has already been run on production machines. Instead, you should write a new migration that performs the changes you require. Editing a freshly generated migration that has not yet been committed to source control (or, more generally, which has not been propagated beyond your development machine) is relatively harmless.

Full article: http://guides.rubyonrails.org/migrations.html#resetting-t...