For someone not familiar with Heroku, it can be a bit daunting to get WordPress and HHVM running on a Heroku web dyno after working on a traditional LAMP stack. That’s why I titled this for beginners because I are one and it took me a while to wrap my head around it. Let me also say that I am not a Heroku master and this tutorial most certainly will be agnostic of some of the more technical aspects of Heroku.
This tutorial is also just a means to get WordPress running on a single dyno (server) using the free tier and has not been tested on an enterprise installation. As a point-of-reference, though technically savvy, I do not use https://github.com/mchung/heroku-buildpack-wordpress because the template they use has actual distribution code committed to the repo which relies on a human to continually update. At this reading, some of the plugins are out-of-date, and I prefer to pull distributions from the source using Composer.