modify readme

README.md

 # react-js-pull-to-refresh
-Pull to refresh on web
+
+Pull to refresh with react
+ > Support all mobile(iOS, Android) and Desktop browser (Chrome, Safari, firefox, Opera, QQ, UC, ... etc)
+
 
 [![npm version](https://badge.fury.io/js/react-js-pull-to-refresh.svg)](https://badge.fury.io/js/react-js-pull-to-refresh)
 [![license](https://img.shields.io/github/license/echoulen/react-js-pull-to-refresh.svg)](https://opensource.org/licenses/MIT)
@@ -14,11 +17,35 @@ or
 `yarn add react-js-pull-to-refresh`
 
 ## Props
-- pullDownContent: JSX.Element (Required)
-- releaseContent: JSX.Element (Required)
-- refreshContent: JSX.Element (Required)
-- pullDownThreshold: number (Required)
-- onRefresh: () => Promise<any> (Required)
+|Name|Type|Required
+|:------:|:------:|:------:|
+|pullDownContent|JSX.Element|true|
+|releaseContent|JSX.Element|true|
+|refreshContent|JSX.Element|true|
+|pullDownThreshold|number|true|
+|onRefresh|Promise|true|
 
 ## Usage
-See examples folder
+
+#### import PullToRefresh
+```js
+import {PullToRefresh} from "react-js-pull-to-refresh";
+```
+
+#### Sample
+```js
+<PullToRefresh
+  pullDownContent={<div style={{backgroundColor: "grey", height: "200px", textAlign: "center"}}>Pull down to refresh</div>}
+  releaseContent={<div style={{backgroundColor: "green", height: "200px", textAlign: "center"}}>Release to refresh</div>}
+  refreshContent={<div style={{backgroundColor: "yellow", height: "200px", textAlign: "center"}}>Refreshing</div>}
+  pullDownThreshold={200}
+  onRefresh={this.onRefresh}
+>
+  <div style={{height: "150vh", textAlign: "center"}}>
+    <div>PullToRefresh</div>
+  </div>
+</PullToRefresh>
+```
+
+## Contributing
+`npm run dev`