docs: added limitation documentation of using reactive

pikax · liximomo · commit bb1e0309ae94 · 2019-09-28T23:12:36.000+08:00
diff --git a/README.md b/README.md
@@ -167,6 +167,11 @@ b.list.push(
 b.list[1].count === 1; // true
 ```
 
+### ***Using*** `reactive` will mutate the origin object
+
+This is an limitation of using `Vue.observable` in Vue 2.
+> Vue 3 will return an new proxy object.
+
 ---
 
 ## `watch()` API
diff --git a/README.zh-CN.md b/README.zh-CN.md
@@ -167,6 +167,11 @@ b.list.push(
 b.list[1].count === 1; // true
 ```
 
+### `reactive` 会返回一个修改过的原始的对象
+
+此行为与 Vue 2 中的 `Vue.observable` 一致
+> Vue 3 中会返回一个新的的代理对象.
+
 ---
 
 ## `watch()` API
