add constraint to service create ref
add constraint to service create ref

Signed-off-by: Charles Smith <dd8094a0ebe127b002d25a204df37082ff5d8b3b@docker.com>

e11137/cli,thaJeztah/cli,ashfall/cli,e11137/cli,docker/cli,Zebrilee/cli,cpuguy83/cli,allencloud/cli,redpanda/cli,ashfall/cli,thaJeztah/cli,dnephin/cli,allencloud/cli,docker/cli,redpanda/cli,riyazdf/cli,Zebrilee/cli,cpuguy83/cli,riyazdf/cli,dnephin/cli