title: facebook login not working php sdk 3.0 oauth2.0
body: <p>I am using facebook api 3.00 (the one from github). When I click on the login link I am redirected to the authentication page of facebook.</p>
  
  <p>When it comes back it's showing the <code>$user</code> as null, but this is working properly:</p>
  
  <pre><code>print $facebook-&gt;getAccessToken()
  </code></pre>