Add Alembic for database migrations and initial migration scripts

- Created alembic.ini configuration file for Alembic migrations.
- Added README file for Alembic with a brief description.
- Implemented env.py for Alembic to manage database migrations.
- Created script.py.mako template for migration scripts.
- Added initial migration script to create database tables.
- Created a migration script to add initial plan and playlist data.
- Updated database initialization to run Alembic migrations.
- Enhanced credit service to automatically recharge user credits based on their plan.
- Implemented delete_task method in scheduler service to remove scheduled tasks.
- Updated scheduler API to reflect task deletion instead of cancellation.
- Added CLI tool for managing database migrations.
- Updated tests to cover new functionality for task deletion and credit recharge.
- Updated pyproject.toml and lock files to include Alembic as a dependency.

app/core/database.py

@@ -8,7 +8,6 @@ from sqlmodel.ext.asyncio.session import AsyncSession
 import app.models  # noqa: F401
 from app.core.config import settings
 from app.core.logging import get_logger
-from app.core.seeds import seed_all_data
 
 engine: AsyncEngine = create_async_engine(
     settings.DATABASE_URL,
@@ -40,26 +39,23 @@ def get_session_factory() -> Callable[[], AsyncSession]:
 
 
 async def init_db() -> None:
-    """Initialize the database and create tables if they do not exist."""
+    """Initialize the database using Alembic migrations."""
     logger = get_logger(__name__)
     try:
-        logger.info("Initializing database tables")
-        async with engine.begin() as conn:
-            await conn.run_sync(SQLModel.metadata.create_all)
-        logger.info("Database tables created successfully")
+        logger.info("Running database migrations")
+        # Run Alembic migrations programmatically
+        from alembic import command
+        from alembic.config import Config
 
-        # Seed initial data
-        await seed_initial_data()
+        # Get the alembic config
+        alembic_cfg = Config("alembic.ini")
+
+        # Run migrations to the latest revision
+        command.upgrade(alembic_cfg, "head")
+        logger.info("Database migrations completed successfully")
 
     except Exception:
         logger.exception("Failed to initialize database")
         raise
 
 
-async def seed_initial_data() -> None:
-    """Seed initial data into the database."""
-    logger = get_logger(__name__)
-    logger.info("Starting initial data seeding")
-
-    async with AsyncSession(engine) as session:
-        await seed_all_data(session)