Mailprobe uses the database migration plugin. The user guide could be found at http://grails-plugins.github.com/grails-database-migration/docs/manual/index.html.
The master DB for all changes is devDB in the mailprobe-core root directory . All commands have to be issued in the mailprobe-core directory.
svn co https://mailprobe.svn.sourceforge.net/svnroot/mailprobe/trunk mailprobe
grails -Dgrails.env=test dbm-update
After changing the domain classes or adding new domain classes you have to diff the master (devDB) against the stable version (testDB).
grails -Dgrails.env=dev dbm-diff test --add change01.groovy
For every diff use a different name for the result file (above example with change01.groovy). The created files will be included in changelog.groovy.
grails -Dgrails.env=test dbm-update grails -Dgrails.env=prod dbm-update
migrates all changes to the XXXX-databases in mailprobe-core root directory. The databases will be created if they don't exist.