Alembic is always a pain in the ass to get working for a new application. Usually my situation is that I spend a couple days working on a new application, only later to think about maintaining my database in some production-esque environment. How do I create my original migration file? This document is the quick and dirty way to bootstrap your alembic configuration.
First, copy over and read through the alembic directory within this code base.
It has wired up the env.py file properly and applied the changes suggested
from the linked resources below.
Second, you want to get rid of invocations of db.create_all. See notes in
the code. TL;DR: You're replacing database table create/upgrade/downgrade
operations with alembic. Calling db.create_all causes thrashing that is hard
to detect and fix.
Third, you want to delete your database to start with a clean start. Delete it,
and run alembic stamp head to indicate this is the current head state of your
database.
Fourth, you want to create your "initial migration" from the head state that
you just stamped (i.e., an empty database) to the new state (i.e., the fully
created/populated database). To do that run alembic revision --autogenerate -m "Initial database setup.". You should see a meaningful migration file created.
You're done. At this point, read through the following resources and become diligent about creating your migration files when you update your database models.
These are some useful Alembic resources for going deeper: