fix: fixed issue that creyPY couldn't be used without PSQL

creyPY/fastapi/db/__init__.py

@@ -1,3 +1,8 @@
-from .async_session import *  # noqa
+try:
-from .helpers import *  # noqa
+    import sqlalchemy
-from .session import *  # noqa
+
+    from .async_session import *
+    from .helpers import *
+    from .session import *
+except ImportError:
+    print("SQLAlchemy not installed. Database functionality will be disabled.")