On the top of my head, I believe it's the same as hosting a Flask app with some differences [1]. But really a quick google search [2] answers your question. Here are some resources found from the search [3][4]. And hey look, something from github [5]
Hope it helps
[1] https://devcenter.heroku.com/articles/getting-started-with-p...
[2] https://www.google.com.au/#q=webpy+heroku
[3] https://coderwall.com/p/g4tqoa
[4] http://www.artima.com/weblogs/viewpost.jsp?thread=335549
[5] https://github.com/CalumJEadie/basic-webpy-heroku-app