Software Engineering Services provides the tool GitLab. GitLab is an open-source-software to host and manage own Git-repositories. Besides the main task of the code-management other functions like a simple issue-tracking-system, a wiki and also an option to review codes are covered. With this GitLab supports the developer, who increase the quality of the developed program codes.
The central RWTH GitLab instance can be used by anyone with RWTH accessibility and the access is granted still the retirement. Externals can also be invited to existing projects.
There is also official documentation for GitLab.