Cil is an easy-to-use command-line driven distributed issue tracker. Using Git as it's storage backend, the power of a distributed version control system can be harnessed to enhance and provide powerful features. Cil saves the issues, comments, and attachments locally in plain-text for ease of use and easy accessibility.
gitolite is an access control layer on top of git. It allows you to setup git hosting on a central server, and have multiple "virtual" users (i.e., not "Unix" users) access multiple git repositories, with fine grained access control (read control at the repo level granularity, write control at branch/tag/file/dir level). It has several other features, comprehensive documentation, does not require root permissions, and does not depend on anything except git, Perl 5.8 or later, and any POSIX shell.
RepoManager offers a minimalistic approach to Web-based management of version control system repositories. Its goal is to simplify effective handling of repository permissions for a large number of users. Using RepoManager, users themselves are able to grant others permissions to use their repositories whenever they want.