public function addRole($roleId, $allowed, $pageId = 0)
    {
        if (!$this->hasRole($roleId, $pageId)) {
            $this->roles()
                ->attach($roleId, [
                    self::PIVOT_ATTR_ALLOWED => $allowed,
                    self::PIVOT_ATTR_PAGE_ID => $pageId,
                ]);
        }

        return $this;
    }