add puppet-sync hook
Originally created by Tails on #5604 (Redmine)
On lizard, run as a post-receive hook:
puppet-sync --branch production \
--deploy /etc/puppet/environments \
--repository gitolite@git.puppet.tails.boum.org:puppet-lizard-manifests
Example recipes can be found at http://sts.ono.at/blog/2010/12/22/synchronize-puppet-with-git/.