Übersicht
Herein lies the source for the software that makes this site tick: redmine, or to be precise, the patched version that fachschaften.org runs on. Some of the changes are quiet heavy-handed and might need some understanding of rails to maintain, or at least some patience and perseverance to report problems here and wait for them to be fixed.
All features are (or should be) in individual git branches, which are then merged in the fsenorg branch. If for example you only want to have the issue field for related issues autocomplete, you should have a look at the autocomplete_related_issues branch.