Craft\m160209_000001_seomatic_addRobotsTxt::safeUp PHP Method

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