Adding Dockerfile/instructions

[karllhughes]

Hey @lionleaf, nice project!

I was doing some local dev on it today and I created a Dockerfile. I'd be happy to make a PR and add some Docker instructions if you'd like?

Just wanted to solicit your thoughts first. Thanks!

[lionleaf]

Thanks @karllhughes !

Docker is one of those things on my list that I've been meaning to get some time to play around with. It seems useful for dwitter, and I'd be happy for a pull request and a forcing function for me to spend some time with it :)