Earlier quoted context omitted.
Heroku doesn't maintain database state. Your dyne can essentially be erased and restarted with an empty database. That's not usable for production systems.
> Heroku doesn't maintain database state. Your dyne can essentially be erased and restarted with an empty database. That's not usable for production systems. Almost, dynos don't persist filesystem changes but for databases you're suppose to host the data elsewhere (e.g. Heroku Postgresq, AWS RDS, AWS S3) and that data will be persisted. This is by design and a very good strategy for production systems as you can then…
Heroku is super easy to use and setup for a newb like me, but never explains this up front. So I was shocked when I figured it out months into using my first dyno. Everything you write makes sense, and hosting my data elsewhere turned out to be easy. But it's definitely an important point to understand, because it adds a layer of cost to hobby projects you want to run full time sites with.