Moved role constraints into model and removed edit deployment

(cherry picked from commit 04abeabde6a64fc0c77850c3d892544805eee6f0)
Merge pull request #137 from vuntz/release/roxy/master

Moved role constraints into model and removed edit deployment
Removed the single assignment block from constraints
Merge pull request #138 from tboerger/feature/roxy/fix-constraints

Removed the single assignment block from constraints