Update doc

Author: Xie, Ziyu

README.md

@@ -139,6 +139,7 @@ Well you can use both directives concurrently if you wish:
     | position | `{ x: number, y: number }` | `{ x:0, y:0 }` | Use it to set position offset |
     | gridSize | number | 1 | Use it for snapping to grid. Refer to [demo](https://xieziyu.github.io/angular2-draggable/#/advance/snap-grid) |
     | preventDefaultEvent | boolean | `false` | Whether to prevent default mouse event |
+    | scale | number | 1 | Set it when parent element has CSS transform scale |
 
 + `ngResizable` directive support following input porperties:
 

src/assets/CHANGELOG.md

@@ -1,7 +1,7 @@
 ## 2.1.9 (2018-11-29)
 
 #### Bugfix
-+ **ngDraggable**: [#31]((https://github.com/xieziyu/angular2-draggable/issues/31)) Problems when scale transform applied to parent. ([by rathodsanjay](https://github.com/rathodsanjay) - [PR #123](https://github.com/xieziyu/angular2-draggable/pull/123))
++ **ngDraggable**: [#31](https://github.com/xieziyu/angular2-draggable/issues/31) Problems when scale transform applied to parent. ([by rathodsanjay](https://github.com/rathodsanjay) - [PR #123](https://github.com/xieziyu/angular2-draggable/pull/123))
 
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