Generic single-database configuration with Alembic.

For more information on Alembic, see:
https://alembic.sqlalchemy.org/en/latest/

To run migrations:
1. Make sure you have alembic installed:
   ```
   pip install alembic
   ```

2. Run the upgrade to the latest version:
   ```
   alembic upgrade head
   ```

3. To create a new migration:
   ```
   alembic revision -m "description of changes"
   ```

4. To downgrade:
   ```
   alembic downgrade -1
   ```

5. To get current migration version:
   ```
   alembic current
   ```

6. To see migration history:
   ```
   alembic history
   ```