Update README.md

Author: Aleksey Masny

README.md

@@ -15,6 +15,12 @@ piPinyin.toPinyin('我');
 piPinyin.recycle();
 ```
 
+How to build jar
+----------
+```bash
+./gradlew clean jar
+```
+
 License
 -------
 
@@ -34,4 +40,4 @@ License
 
 
 
- [1]: https://code.google.com/p/pinyin4android/
+ [1]: https://code.google.com/p/pinyin4android/