We currently build from Git via Puppet, but an alternative forward way would be to move the WAR build into a separate package which generates a deb for deployment (to be run from boron). That's specifically useful when we've more than one CAS server and will also make it simpler to e.g. build a new version for testing in the staging environment.
We could even upload such a package to Debian (while a fully fledged CAS build into Debian seems a too huge undertaking given the complexity and modularity of the current deployment approach by upstream.