working 3 tier approach

backend/app/database.py

@@ -0,0 +1,11 @@
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+
+from app.config import settings
+
+engine = create_async_engine(settings.DATABASE_URL, echo=False)
+async_session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
+
+
+async def get_session() -> AsyncSession:
+    async with async_session() as session:
+        yield session