Add rudimentary migration testing
Add rudimentary migration testing

We start at version 0 and apply each migration one at a time.

bp db-migration-testing

Change-Id: If098d9baeca4c58e19b23fac69bcb48a3d6c072a

ramsateesh/designate,cneill/designate,cneill/designate-testing,kiall/designate-py3,muraliselva10/designate,melodous/designate,ionrock/designate,kiall/designate-py3,kiall/designate-py3,grahamhayes/designate,ramsateesh/designate,ionrock/designate,openstack/designate,melodous/designate,ramsateesh/designate,grahamhayes/designate,muraliselva10/designate,melodous/designate,grahamhayes/designate,cneill/designate-testing,cneill/designate,tonyli71/designate,openstack/designate,tonyli71/designate,richm/designate,muraliselva10/designate,cneill/designate-testing,openstack/designate,NeCTAR-RC/designate,cneill/designate,kiall/designate-py3,ionrock/designate,richm/designate,kiall/designate-py3,NeCTAR-RC/designate,cneill/designate,melodous/designate,tonyli71/designate,cneill/designate