code: public function save($group, $folder = null) {
  
          //Save the user config
          $configini = \Library\Config::$ini;
          $fileHandler = \Library\Folder\Files::getInstance();
          $userfolders = $this->config->getParam('site-users-folder', '/users');
  
          $prefdir = FSPATH . $userfolders . DS . $this->user->get("user_name_id") . DS . 'preferences' . DS;
  
          if (!$fileHandler->is($prefdir, true)) { //if its not a folder
              $folderHandler = \Library\Folder::getInstance();
              if (!$folderHandler->create($prefdir)) {
                  $this->setError(_("Could not create the target uploads folder. Please check that you have write permissions"));
                  throw new \Platform\Exception($this->getError());
              }
          }
  
          $paramsfolder = str_replace(array('/', '\\'), DS, $prefdir);
          $paramsconf = array( $group );
          $filename = $group.".ini";
          if ($configini::saveParams($filename, $paramsconf, $paramsfolder) == FALSE) {
              $this->setError($this->config->getError());
              return false;
          }
          
          return true;
      }
docs: Saves options to the database, inserting if none exists or updating on duplicate key
  
  @param array $options An array of options
  @param string $group A unique string representing the options group
  @return boolean