Craft\m160704_000000_retour_addReferrerStats::safeUp PHP Method

    public function safeUp()
    {
        // specify columns and AttributeType
        $newColumns = array('referrerUrl' => ColumnType::Varchar);
        $this->_addColumnsAfter("retour_stats", $newColumns, "redirectSrcUrl");
        // return true and let craft know its done
        return true;
    }