Update README.md

README.md

@@ -39,6 +39,14 @@ p2pspider(
 );
 ```
 
+或者使用 `Promise` 替代回调函数：
+
+```js
+p2pspider(options).then(function(metadata) {
+    console.log(metadata);
+});
+```
+
 **目前只能放在有公网 IP 的主机上执行, 或者路由器设置端口转发.**
 
 ## 待做
@@ -112,6 +120,14 @@ p2pspider(
 );
 ```
 
+Or using `Promise` instead of callback functions:
+
+```js
+p2pspider(options).then(function(metadata) {
+    console.log(metadata);
+});
+```
+
 **p2pspider only run on a host which has dedicated public IP.**
 
 ##Upcoming features
@@ -141,4 +157,4 @@ When I was developing this project, I references some code from [bittorrent-prot
 Please don't share the data p2pspider crawled to the internet. Because sometimes it crawls sensitive/copyrighted/porn data.
 
 ##License
-MIT
+MIT