update docs/component/_sidebar.md.

docs/component/_sidebar.md

@@ -53,6 +53,7 @@
       * [微信小程序](component/ad-weixin.md)
       * [微信小程序格子广告](component/ad-grid.md)
       * [广告错误码](component/ad-error-code.md)
+    * [uniCloud-db云数据库](/uniCloud/unicloud-db.md)
     * [页面属性配置节点](component/page-meta.md)
       * [page-meta](component/page-meta.md)
       * [navigation-bar](component/navigation-bar.md)