Update README to use standard docker image format
Update README to use standard docker image format

[#86357202]
cloudfoundry-samples/lattice-app,gstackio/sample-app,hpcloud/lattice-app,pivotal-cf-experimental/lattice-app,cloudfoundry-samples/lattice-app,DieterVennekens/test-app,hpcloud/lattice-app,davidwadden/lattice-app,aripka-pivotal/lattice-app,cloudfoundry-samples/test-app,aripka-pivotal/lattice-app,davidwadden/lattice-app,cloudfoundry-samples/test-app,pivotal-cf-experimental/lattice-app,DieterVennekens/test-app,gstackio/sample-app