Moved role constraints into model and removed edit deployment

(cherry picked from commit 8b54013e59972d38d4dfff9ba1f807e642e66412)
Merge pull request #88 from vuntz/release/roxy/master

Moved role constraints into model and removed edit deployment
Removed the single assignment block from constraints
Merge pull request #89 from tboerger/feature/roxy/fix-constraints

Removed the single assignment block from constraints