/**
  * Sets some piece of information to use to identify the current user
  *
  * @param  mixed $token  The user's token. This could be a user id, an email address, a user object, etc.
  * @return void
  */
 public static function setUserToken($token)
 {
     fSession::set(__CLASS__ . '::user_token', $token);
     fSession::regenerateID();
 }