Doesn’t work.
I’ve been trying in vain to deploy a very light Sqlite database, supporting a github-login authenticated timetable tool, only to run into walls repeatedly.
Then I realized that Heroku doesn’t work with Sqlite, because, of course, files don’t persist across deploys. Facepalm.
So the only viable option is to use postgress/mysql on production, adding yet another minimal $9 per month to the bill.
Heroku is great for quick projects. However, cost-effective wise, not so much.