Issue
You want to toggle auto-provisioning of a Heroku Postgres database on the first deployment of your apps and are unsure how to enable this behavior.
If you created your account before May 15, 2023, your Ruby, Python Django, Java and Scala apps automatically create a PostgreSQL database if it has a Postgres database adapter dependency. This provisioning happens only on the first deployment.
Apps belonging to accounts created after May 15, 2023 don't automatically provision a database on first deployment.
You can enable or disable this auto-provisioning behavior on your account.
Resolution
To toggle this behavior, open a support ticket. Choose General Platform Features -> Builds, with subject "Toggle DB Auto-Provisioning". You must indicate in the issue description if you're requesting to enable or disable the feature and include a reference link to this article.
Regardless of auto-provisioned behavior, you can always provision a database on your own