I would put it the other way around. Docker+Vagrant is best used for deployment and hopefully it will be stable and battle-tested enough so I can use it in prod

I would put it the other way around. Docker+Vagrant is best used for deployment and hopefully it will be stable and battle-tested enough so I can use it in production. I love the fact that once I configured the dev environment on my PC and I hit the road on the next day I can have exactly same environment on my laptop by running single line - "vagrant up". Not to mention that any dev working on the same project saves himself ton of time but not having to configure everything from scratch. I have not taken the leap of faith yet and I am not using the docker in production but hopefully this will happen soon.