Automate building and pushing images for users with repo2docker action

[yuvipanda]

Summary

Users should ideally have full control over the images their hub runs. Setting up GitHub repositories with automatic building via GitHub actions + repo2docker-action is the best way to do this. It sticks to standards, plus people can test out their image on mybinder.org!

Tasks

We need a couple new features in repo2docker-action for this to fully work.

• Create a template repo + documentation for hub user image repos #631
• Support pushing to multiple registries Support pushing to multiple registries jupyterhub/repo2docker-action#70
• Complete Support and document pushing to AWS ECR jupyterhub/repo2docker-action#65 and make sure that it is possible to do this via the action
• Update our documentation to highlight this pattern, pointing to repo2docker action docs for the details
  • the template repository created by Create a template repo + documentation for hub user image repos #631
  • the pilot documentation` (maybe around here: https://pilot.2i2c.org/en/latest/admin/howto/environment.html#customize-your-hub-environment)
• Documentation in repo2docker-action
  • Add documentation about pushing to GCR, GAR and Azure container registry instructions in Document a few image repositories, with some guidance for which to use jupyterhub/repo2docker-action#61 ➡️ Document pushing to Google registries and Azure jupyterhub/repo2docker-action#80
• 2i2c-specific documentation about this ➡️ Mention that pushing to other registries is possible hub-user-image-template#4
  • Mention in the template repository that there are multiple registries they can push to, then point people to the repo2docker-action for the actual docs
  • Mention that for cloud provider-specific registries, if we are running the cluster on our projects, then we'll need to give you credentials for it

[choldgraf]

In today's sprint meeting we decided to try and finish this one up this week, but if @GeorgianaElena runs into any snags in the coming days, we should re-assess and decide to re-scope. Our current thinking is that this one is now mostly a matter of documentation and figuring out the right pattern, but we might be wrong there!

[choldgraf]

hey @GeorgianaElena where are we on this one? maybe at tomorrow's sprint meeting we can discuss what are the next steps to close this one out.