/**
  * @param string $site
  */
 public function __construct($site)
 {
     $this->_site = $site;
     parent::__construct(ProjectModelMongoMapper::instance());
 }
 /**
  * Creates a user join request by adding the $userID to the join request array on the project
  * @param string $userId
  * @param string $role the system role the user has
  * @see roles
  */
 public function createUserJoinRequest($userId, $role)
 {
     $mapper = ProjectModelMongoMapper::instance();
     $model = new ProjectRoleModel();
     $model->role = $role;
     $this->userJoinRequests[$userId] = $model;
 }