add Usage tip

Author: xiaoping6688

README.md

@@ -1,2 +1,19 @@
 # node-socket
 TCP Socket with TLV packet （Node端基于TLV二进制协议格式进行封装的socket工具库，包括粘包断包处理）
+
+
+## Install
+
+```
+$ npm install --save node-socket
+```
+
+
+## Usage
+
+```js
+const socket = require('node-socket')
+socket.connect(port, host, onConnected, onReceived, onClosed)
+
+//=> @see example.js
+```