Solution for the BouncyBall exercise

Spec: https://github.com/hfour/exercises/tree/master/bouncing-balls

Run & Test:

1. NodeJs is installed 
    If nodejs is installed on the machine, simply run `node app` in the root folder of the app
    Go to `<LOCALHOST>:3000` in the browser and enjoy.

2. NodeJs not installed, Docker available
    If nodejs is NOT installed on the machine(or you simply want to run the app in a Docker container), you can 
    build the image by runnng `docker build -t <IMAGE_NAME> .` in the root folder of the app.
    You can than spin up a container with `docker run -p <PORT>:3000 [-d] <IMAGE_NAME>`.
    Go to `<LOCALHOST>:<PORT>` in the browser and enjoy.