possibility for an admin to configure administration mail address
Merge branch 'develop-ak' of github.com:tkowark/hpi-hiwi-portal into develop-ak
tests + refactoring of configuration stuff
Merge branch 'develop-ak' of github.com:tkowark/hpi-hiwi-portal into develop-ak
tests for email validation
Merge branch 'develop-ak' of github.com:tkowark/hpi-hiwi-portal into develop-ak