Update README with details of StackForge build
Update README with details of StackForge build

Change-Id: Ic657b8bf80934f2445f1544f9f3e007cc2eba93d

sapcc/monasca-thresh,openstack/monasca-thresh,stackforge/monasca-thresh,stackforge/monasca-thresh,openstack/monasca-thresh,openstack/monasca-thresh,sapcc/monasca-thresh