Yeah, I have been looking for something similar!
there is no documentation on redmine but the only feature
that I am aware is that if you append a dash (#) and a issue
number you get a link to that issue.
For example:
$ git commit -a -m '#45 makes earth rotate in reverse!'
would be on visible on the repository and the number will link
to the issue #45!
I really want to make it so if a commit is liked to a specific
issue the commit-message gets appended to the issue.
and yes, close, fixed and stuff like that would be great!
I've been browsing for such (git-hooks) or features in redmine for
a while but not much luck! (their documentation sucks!)
somebody post some updates on this topic!