Moved role constraints into model and removed edit deployment

(cherry picked from commit bdf3e3bed88227fe74fb1f046e572a0a1c3487a6)
Merge pull request #42 from vuntz/release/roxy/master

Moved role constraints into model and removed edit deployment
Removed the single assignment block from constraints
Merge pull request #43 from tboerger/feature/roxy/fix-constraints

Removed the single assignment block from constraints