Fixes#129
## How to test
1. Log in as `evan@example.com`
2. Go to "My groups"
3. Click "Create new group"
4. Select some projects but do *not* fill in the "Title"
5. Click save
6. Error message should be presented
7. Project selection should be maintained
Co-authored-by: Nico Athanassiadis <nico@dsv.su.se>
Reviewed-on: #133
Reviewed-by: Nico Athanassiadis <nico@dsv.su.se>
Co-authored-by: Andreas Svanberg <andreass@dsv.su.se>
Co-committed-by: Andreas Svanberg <andreass@dsv.su.se>