Dockerize the shiny app

[colinxfleming]

This sets up a docker container to run the shiny server, albeit ugly.

I didn't do a volume - the image needs shiny stuff to be set up in /srv/shiny-server and I'm not savvy enough to figure that out. But, like, starting the server works!

@DarthHater could you spot check my work here, and if you want suggest any linux pkgs to add in setup given that we'll probably be running something similar to this in prod, I'm def all ears. These images are debian based, I believe. You should be able to recreate with instructions in the readme.

Fixes #9
Bumps #3

[DarthHater]

Based on my reading of the base shiny image I see:

https://github.com/rocker-org/shiny#connecting-app-and-log-directories-to-host

or:

https://github.com/rocker-org/shiny/blob/master/docker-compose.yml#L27

As well from their example docker-compose.yml: https://github.com/rocker-org/shiny/blob/master/docker-compose.yml#L23

I haven't run this yet but mounting logs to a local volume sounds good in theory, makes the app less stateful (you can kill the docker etc... and the logs live on somewhere)

In their example docker-compose.yml they have it run under root to run on port 80, is there a config for port? I'd imagine a production deployment of this would use nginx in front of it so you could pass 443 to whatever port you have open. Just curious on that!

[colinxfleming]

I think for the port thing that's going to be pretty dependent on heroku, which I think doesn't do compose, so we can figure that out when we get to it.

The logs thing totally doable, I rigged up a log dir appropriately. Let me see if I can set up the app itself to link with a volume too.

[colinxfleming]

rough edges should be sanded off now.