Dockerize this app

[jhsu802701]

This app should be Dockerized. (I will submit a pull request for this.)

The setup instructions in CONTRIBUTING.md are geared for running this app in the host environment. I do not like to rely on my host environment for development, because this can lead to the infamous "but it works on my machine" problem. There are too many chances for human error, and setup problems can be difficult to troubleshoot.

The solution is to Dockerize this app with a Dockerfile and docker-compose.yml file. This would provide a universal setup for all current and future contributors and greatly speed up the onboarding process. Furthermore, this makes troubleshooting easier by removing changes for human error in the setup process.