I got an email from a reader about this. Here’s my answer:

It’s been a while since I wrote that Heroku post, so there may be a better way now than what I was doing then. I think I remember that Heroku has its own way of managing environment variables, so you’ll need another package.

I just looked, and it seems like my whole post from back then has been greatly simplified to just two easy steps in the Heroku docs: https://devcenter.heroku.com/articles/heroku-postgresql#connecting-with-django

Hope this helps!