title: Facebook Graph Api Is it possible to know, if a user use a specific application, or game
body: <p>Using Facebook Graph Api, is it possible, for a web site with FB Login implemented, to know if a user use, or have installed, a specific application, or game.</p>
  
  <p>I want to create a community around certain game on facebook, and would use this to prevent non user of the app to register on my site.</p>