I have just updated my app from Rails 2.3.5 to Rails 3. One of the plugins I liked most was Auto Migrations by Dizzy: http://www.dizzy.co.uk/ruby_on_rails/contents/auto-migrations
This allowed me to make changes in the database simply by altering the schema then running db:auto:migrate.
This plugin does not seem to be working in Rails 3. Do you guys know either how to get it working or do you know of other migration tools I can use to automatically migrate my existing (long) schema into my new empty database?