title: Login with facebook or google using Oauth2 library in symfony2
body: <p>I am using fosuserbundle for login and registration in my symfony 2.6 project.
  Now I want to allow user to login via facebook or google account. </p>
  
  <p>I want to use Oauth2 library of friendsofsymfony getting from here <a href="https://packagist.org/packages/friendsofsymfony/oauth2-php" rel="noreferrer">https://packagist.org/packages/friendsofsymfony/oauth2-php</a></p>
  
  <p>I have installed library using "friendsofsymfony/oauth2-php": "1.1.*@dev" in composer.phar and updated vendors. But I am not able to find out the documentation which can show the steps to configure and use in login.</p>
  
  <p>It should work with fosuserbundle. Can anyone suggest me where can I get steps how can I use Oauth2 library in my project?</p>