Git hooks for sending commits to a mailing list?

Before the change over to gitlab, I had set up a git post-receive hook
so that all commits were sent to the cmucl-commit (and cmucl-cvs) mailing
lists.  (The hook also automatically updated a trac issue, but that
seems not necessary anymore with gitlab.)

I can't seem to find out how to do that now.  There's a page on web
hooks, but I can't easily tell what I'm supposed to do with that.  I
just want each commit to be sent to the cmucl-commit mailing list.

-- 
Ray