diff --git a/Merge/back_wzy/extensions.py b/Merge/back_wzy/extensions.py
new file mode 100644
index 0000000..3563787
--- /dev/null
+++ b/Merge/back_wzy/extensions.py
@@ -0,0 +1,6 @@
+# extensions.py（根目录，同级于 app.py）
+from flask_sqlalchemy import SQLAlchemy
+from flask_migrate    import Migrate
+
+db      = SQLAlchemy()
+migrate = Migrate()