如何在iOS App / Server中使用OAuth 2.0 Google+注册来创建用户帐户？

I'm making an iOS app—I want it to have Google+ Signup/Login. I have a server that works all fine with normal accounts. It works where you send up a username and password and it gives a token which is what is saved on the device—and used for making any requests from the app. I'm making an iOS app—I want it to have Google+