Hosted instance

[akleemans]

Hey, I noticed that the README (and also the "About" part of the repo) still links to the Heroku-App which hasn't been available for quite some time. Since I am hosting an instance for about a year and a half now, maybe the links could point there? => https://pyth-docker.azurewebsites.net/. I plan to keep it running for at least the upcoming 3 years.
This way if someone visits the repo they are not greeted with a dead link.