public function addArticle($articleId)
    {
        $oDb = \OxidEsales\Eshop\Core\DatabaseProvider::getDb();
        $sQ = "select max(oxsort) from oxactions2article where oxactionid = " . $oDb->quote($this->getId()) . " and oxshopid = '" . $this->getShopId() . "'";
        $iSort = ((int) $oDb->getOne($sQ)) + 1;

        $oNewGroup = oxNew(\OxidEsales\Eshop\Core\Model\BaseModel::class);
        $oNewGroup->init('oxactions2article');
        $oNewGroup->oxactions2article__oxshopid = new \OxidEsales\Eshop\Core\Field($this->getShopId());
        $oNewGroup->oxactions2article__oxactionid = new \OxidEsales\Eshop\Core\Field($this->getId());
        $oNewGroup->oxactions2article__oxartid = new \OxidEsales\Eshop\Core\Field($articleId);
        $oNewGroup->oxactions2article__oxsort = new \OxidEsales\Eshop\Core\Field($iSort);
        $oNewGroup->save();
    }