title: Pull and Push image to another project using GCloud container builder
body: <p>I have 2 gcloud projects, say <code>foo</code> and <code>bar</code>. And I have a docker image named <code>gcr.io/foo/cat:latest</code> in the container registry of <code>foo</code> project. Need a way to promote this image to <code>bar</code> project while renaming the tag to <code>gcr.io/bar/cat:1.0.0</code>. How to do this within the gcloud container service of <code>bar</code> project ?</p>