title: How can I invite other Facebook users to my iPhone app with extras?
body: <p>If I want to get information about a user's friends in an iPhone app that integrates Facebook SDK, how do I ask the user to invite their friends to use the app and once the friend accepts the invite to ask those people to provide the "user_relationship_details" permission?</p>
  
  <p>In other words, what code or methods do I use?</p>