title: How to allow users of my site to login/register via Facebook and integrate Facebook login system with my own login system?
body: <p>I am just lost and do not know where to begin, please show me documentation I can read to let users register/login to my site using Facebook.</p>
  
  <p>Assuming that </p>
  
  <ul>
  <li>I have my own registration/login system</li>
  </ul>
  
  <p>How can I</p>
  
  <ul>
  <li>Log in users with their Facebook profile</li>
  <li>Register users quickly with their Facebook profile if they are not registered</li>
  </ul>
  
  <p>Any ideas or docs are appreciated. </p>