Gerrit has a feature that allow setting labels, reviewers, and topic on push[1] of a new change or patchset.  I would also like the ability to set a comment message on a push.  something like: push origin HEAD:refs/for/master%m="This patchset is just a rebase on current master."

[1] https://review.openstack.org/Documentation/user-upload.html#push_create