docs: 更新 README

Author: mathink12

README.md

@@ -2,6 +2,9 @@
 
 JSON tree view for Vue.
 
-[Demo | Docs](https://mathink12.github.io/json-tree/)
+|                         GitHub                        |                        Gitee                        |
+|-------------------------------------------------------|-----------------------------------------------------|
+| [Repository](https://github.com/mathink12/json-tree) | [Repository](https://gitee.com/mathink12/json-tree) |
+| [Demo & Docs](https://mathink12.github.io/json-tree/) | [Demo & Docs](http://mathink12.gitee.io/json-tree/) |
 
 ![demo](./docs/imgs/json-tree.gif)