Compose: Proposal: add Docker save and load commands

[ebuildy]

Is your feature request related to a problem? Please describe.
Docker can save and load image as tar archive, docker-compose not.

Describe the solution you'd like
a simple docker-compose save > compose.tar.

Describe alternatives you've considered
Parsing docker-compose.yml file to get image list, then run manually docker save:

docker save -o docker-images.tar $(docker-compose config | awk '{if ($1 == "image:") print $2;}' ORS=" ")

[ijc]

Thanks for the suggestion, this sounds like a reasonable enhancement, I think we'd be happy to take a look at a PR implementing this.

[ebuildy]

Thanks you, do you thing this is an easy one? I could spend some time on it if yes.

[ijc]

I woudn't say completely trivial, but at the easier end of the spectrum I reckon.

[Ryllau]

I was wondering if this has been implemented yet?