update readme

README.md

@@ -215,6 +215,7 @@ The slider returns a slider object with some properties and methods once it's in
   play: play(),
   pause: pause(),
   isOn: isOn, // Boolean
+  rebuild: rebuild(),
   destroy: destroy()
 }
 ```
@@ -293,6 +294,13 @@ Destroy the slider.
 slider.destroy();
 ```
 
+#### rebuild
+Rebuild the slider after destroy.
+```javascript
+slider = slider.rebuild();
+// this method returns a new slider Object with the same options with the original slider
+```
+
 ## Custom Events
 Available events include: `indexChanged`, `transitionStart`, `transitionEnd`, `touchStart`, `touchMove` and `touchEnd`.
 ```javascript