liquibase-rails is a Rails compatible gem to allow Liquibase to be embedded well within a JRuby on Rails project. This gem was extracted from a production project (1.5m p/v day) that shares a schema between Java-based and Rails-based front ends.
Get the cutting edge at version at:
http://github.com/redbeard/liquibase-rails
Currently compatible with Liquibase 1.9.1, should be fully compatible with 2.0 shortly.