Update

backend/manage.py

@@ -0,0 +1,14 @@
+from flask_script import Manager
+from flask_migrate import Migrate, MigrateCommand
+
+from flask import current_app as app
+from . import db
+
+migrate = Migrate(app, db)
+manager = Manager(app)
+
+manager.add_command('db', MigrateCommand)
+
+
+if __name__ == '__main__':
+    manager.run()