title: PHP-GitHub-Api Authentication Issue
body: <p>I am trying to authenticate a user using the <a href="https://github.com/KnpLabs/php-github-api">php-github-api</a> library. So far I have sent the user to Github to allow my application access and I successfully get a token back. I'm not sure what to do now. Here is my code.</p>
  
  <p>The URL I send the user to Github with.</p>
  
  <pre><code>https://github.com/login/oauth/authorize?scope=repo,user&amp;client_id=&lt;client_id&gt;
  </code></pre>
  
  <p>Then with the php-github-api I am doing this. The $token variable is the code that is sent in the $_GET array when the user is redirected to the callback.</p>
  
  <pre><code>        $client = new \Github\Client();
          try {
              $auth = $client-&gt;authenticate($token, Github\Client::AUTH_HTTP_TOKEN);
          } catch (Exception $e) {
              dp($e);
          }
  </code></pre>
  
  <p>Does anyone know if this is the correct method to authenticate a user? When I try and call a method the requires an authenicated user I get a 401 status code and an error in return.</p>
  
  <p>Thanks in advance!</p>