The GRAG 1.1 release has improved many-to-many relations support, is fully compliant with Grails 1.1 and fixes some bugs.
GRAG is a free domain object generator for the Grails framework.
With GRAG you can reverse engineer an existing database and generate your Grails domain objects from it.
You can use The GRails Application Generator (GRAG) to get started with Grails using an existing database.
It will generate Grails domain objects including constraints and relations. After generating the domain objects, you can continue using Grails with all it's power.
Take a look at: http://grag.sf.net
And download the final release from: http://sourceforge.net/projects/grag/files/