container_name: A running docker container. Can't be set if image_name is too.
project: Project ID for this request, default as set by gce_get_global_project
This will only work on the Google Container optimised containers of image_family google_containers. Otherwise you will need to get a container authentication yourself (for now)
It will start the push but it may take a long time to finish, especially the first time, this function will return whilst waiting but don't turn off the VM until its finished.
container_url: The URL of where to save container
Returns
A tag for use in Google Container Registry
See Also
Other container registry functions: gce_list_registry, gce_pull_registry, gce_push_registry