add database

app/db/database.py

@@ -0,0 +1,12 @@
+from config import DATABASE_URL
+from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
+from sqlalchemy.orm import declarative_base, sessionmaker
+
+engine = create_async_engine(DATABASE_URL, echo=True)
+Base = declarative_base()
+async_session = sessionmaker(bind=engine, expire_on_commit=False, class_=AsyncSession)
+
+
+async def get_session() -> AsyncSession:
+    async with async_session() as session:
+        yield session