add react-native project "Gank.io 客户端"

项目目前已经可以完美兼容iOS/Android,并且适配了多种大小的屏幕（平板没有做适配）

Author: poberwong

README.md

@@ -186,6 +186,9 @@ https://github.com/facebook/react-native/tree/master/Examples
 * react-native-dribbble-app
 https://github.com/catalinmiron/react-native-dribbble-app
 
+* **Gank.io客户端**
+https://github.com/Bob1993/React-Native-Gank  
+
 * **Leanote for iOS(云笔记)**
 https://github.com/leanote/leanote-ios-rn