Upgrade to grails 2.2.3
Fix #11, use Hibernate DB strategy 'update' instead of 'create-drop' at startup because cloudbees zero-downtime deployment may stop the old version after starting the new one and thus, the old version Hibernate will drop the tables.
Merge pull request #12 from cyrille-leclerc/master

Upgrade to Grails 2.2.3 + fix #11