Support for pkgdb teams.

In the latest release of pkgdb2, there was support for teams added.
Now we need to listen to FAS as well as pkgdb to be triggered: if a user
is added to a group, we need to know that so that we can regenerate the
gitolite bits.
Merge pull request #4 from fedora-infra/feature/teams-support

Support for pkgdb teams.