The git repos need an access control and a general management layer.
Gitolite seems to be the best choice: http://gitolite.com/gitolite/
Gitolite can also be integrated into redmine:
Maybe it makes sense to install this redmine plugin so that all important functionality is available from within one application.
IMPORTANT: For using redmine-git-hosting it is highly recommended to run redmine with nginx, NOT with apache, see http://redmine-git-hosting.io/how-to/install-redmine/