Wercker has a post on continous integration for containers to Kubernetes which Micha, their CEO, did back in June: http://blog.wercker.com/2015/06/23/Deploying-minimal-contain..., which uses Google's Container Registry for pushing images.

If anyone is interested, I just wrapped up a similar post for deploying containers to Giant Swarm from Wercker, no Docker required: I just got done doing a continuos integration post for containers using Wercker and Giant Swarm: https://github.com/giantswarm/swarm-wercker.