/**
  * This adds a shortcut pointing to an existing folder to the current folder
  *
  * @author KnowledgeTree Team
  * @access public
  * @param int $folder_id The ID of the folder to create a shortcut to
  * @return KTAPI_Folder
  */
 function add_folder_shortcut($folder_id)
 {
     $user = $this->can_user_access_object_requiring_permission($this->folder, KTAPI_PERMISSION_WRITE);
     if (PEAR::isError($user)) {
         return $user;
     }
     $oFolder = Folder::get($folder_id);
     if (PEAR::isError($oFolder)) {
         return $oFolder;
     }
     $user = $this->can_user_access_object_requiring_permission($oFolder, KTAPI_PERMISSION_READ);
     if (PEAR::isError($user)) {
         return $user;
     }
     $folder =& KTFolderUtil::createSymbolicLink($folder_id, $this->folder, $user);
     if (PEAR::isError($folder)) {
         return new PEAR_Error(KTAPI_ERROR_INTERNAL_ERROR . ' : ' . $folder->getMessage());
     }
     return new KTAPI_Folder($this->ktapi, $folder);
 }