add flask sqlalchemy

teufa/app.py

@@ -1,7 +1,9 @@
 from flask import Flask
 
+from .ext import db
+
 
 def create_app():
     app = Flask(__name__)
-    app.config["A"] = 1
+    db.init_app(app)
     return app

teufa/ext.py

@@ -0,0 +1,3 @@
+from flask_sqlalchemy import SQLAlchemy
+
+db = SQLAlchemy()