Added back db_migrate.py

db_migrate.py

@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Database migration script for Nyaa.
+Compatible with Python 3.13 and Flask-Migrate 4.0.
+"""
+import sys
+from typing import List
+
+from flask_migrate import Migrate
+from flask.cli import FlaskGroup
+
+from nyaa import create_app
+from nyaa.extensions import db
+
+app = create_app('config')
+migrate = Migrate(app, db)
+
+def create_cli_app():
+    return app
+
+cli = FlaskGroup(create_app=create_cli_app)
+
+if __name__ == "__main__":
+    # Patch sys.argv to default to 'db'
+    if len(sys.argv) > 1 and sys.argv[1] not in ['--help', '-h']:
+        if sys.argv[1] not in ['db', 'routes', 'shell', 'run']:
+            args: List[str] = sys.argv.copy()
+            args.insert(1, 'db')
+            sys.argv = args
+
+    cli()