adding google auth to my react native app code example

Example: how to add oAuth google signin in react native app

import { GoogleSignin, GoogleSigninButton } from 'react-native-google-signin'; 
render() {  
  <GoogleSigninButton 
  style={{ width: 192, height: 48 }}
  size={GoogleSigninButton.Size.Wide}
  color={GoogleSigninButton.Color.Dark}
  onPress={this._signIn}
  disabled={this.state.isSigninInProgress} />
};