add folder operation and use createQueryRunner

src/user/user.service.ts

@@ -10,7 +10,7 @@ import { JwtService } from '@nestjs/jwt';
 export class UserService {
   constructor(
     @InjectRepository(User)
-    private userRepository: Repository<User>,
+    private readonly userRepository: Repository<User>,
 
     private jwtService: JwtService
   ) { }