Resolve failing build

group_creator and possibly project_matcher should be refactored and tested. For instance, it is not possible to test the method in depth after refactoring it. (should be made an issue!)

Currently, locally my tests fail probably due to a newer version of Ruby. I'll switch to an older one for now.

Please make sure that creating groups and project matching works properly when reviewing due to refactoring, I do not know how to test it manually atm.