The Gant master repository is the Git repository held at GitHub, see https://github.com/Gant/Gant People should fork this on GitHub, clone to their local machine, create a feature branch so that master remains a mirror, create changes (with tests, of course) and then create a pull request.
The Git repository on Codehaus is now an administrative mirror and should not be used as the mainline repository, that is the one noted above on GitHub.