Dockerize pixelcite for easier deployment

adds 2 new files to the repo to make a docker version of pixelcite.

testing:

1. `make build`
2. `make run`
3. browse localhost:8000 you should see

The above only works if you have the secret magic config files. I'll try to make sure that's documented on the wiki.
I added these, but I didn't end up using them. I have an 'env-docker' (you can see in the makefile) but it's empty. It's for future twitter integration I didn't get around to.