Add Health checking

[yukiisbored]

Healthcheck is a new-ish feature in Docker to check the actual status of the services/daemons of the container. Healthcheck can be implemented by having a "check command" like using curl to see if it returns 200 or not. It's preferable (for now) to add healthcheck on the compose file rather than the dockerfile.

[yukiisbored]

https://docs.docker.com/engine/reference/builder/#healthcheck