What type of PR is this?

/kind feature

What happened:
Hi,
I am trying to use Dockerhub instead of a local docker registry/ Harbor.

I tried to connect ormb with my dockerhub registry with:

ormb login registry.hub.docker.com -u USERNAME -p MY_PASSWORD
ormb save ./examples/PMML-model  docker.io/USERNAME/models:ormb_pmml_v1
ormb push docker.io/USERNAME/models:ormb_pmml_v1

I can login and save but push send this error:
failed commit on ref "manifest-sha256:7c5eac5fc9f76180b867c4ee67d03e51a43794365a7517aca4c83ce51faa8eb7": unexpected status: 403 Forbidden
It sounds like it is a permission issue to send the model to Dockerhub.

Questions:

• Is this already possible to use DockerHub registry.
• If yes do you have an example?
• if no, is this a feature that can be added in the future?

Thanks!