You can also deploy from GitLab, see https://about.gitlab.com/2016/08/26/ci-deployment-and-enviro... for an introduction.

I'm working on an open source project that does just that: deploy container updates. It's not available just yet, but you can follow me for when I announce it. https://twitter.com/jadbox

Gitlab-ci can do this easily with the gitlab-ci-multirunner docker image. My CI/CD spins up multirunners in autoscaling groups and those said multirunners (it's basically a docker container with privilege mode to spin up the Dockerfiles of whatever you're building) handle the builds, whether they're node or ruby or anything else I've made into docker images.

Check out Distelli - https://www.distelli.com

Disclaimer: I'm the founder

I haven't tried it, but I think you just do "docker pull <your gitlab repo index url>".