Arvados

We're set up to trigger ci.commonwl.org on git push, however the testing actually uses the arvados/arvbox-demo Docker image, so it should trigger on the Docker upload. Can we set up this jenkins plugin?

https://github.com/jenkinsci/dockerhub-notification-plugin/blob/master/README.md#configuring-docker-hub

Coordinate with Michael Crusoe (michael.crusoe@gmail.com) who is responsible for ci.commonwl.org as necessary.