[Feature Request] Add ability to update containers

[deadmeu]

I'm not sure how feasible this would be, but it would be great if there was a simple way to pull the latest version of containers with a simple update button. I'm quite new to using containers and am having some difficulty understanding how to easily update all of my containers without damaging existing data/config.

Automatic version checking would be nice too, as a way to let the user know when containers have a new version available to be pulled.