Managing migration version numbers in Rails among multiple developers using the same database is a pain in the ass. You know the drill, you svn up, create a migration, try to run db:migrate but low and behold, the db version is already 10 versions above your migration's.
This plugin offers a simple solution: create and manage a "history" table that records which migrations have and have not been run and modify rake db:migrate to behave accordingly.
For documentation, installation and usage instructions, please see the migration_izzle github page (scroll down).