Add bouncing-ball component (#72)

Author: hankzhuo

README.md

@@ -481,6 +481,9 @@ https://github.com/shoutem/ui
 * **BlankApp UI** - 高可定制和主题化的 React Native 组件库
 https://github.com/blankapp/ui
 
+* **React Native Bouncing Ball** - 在屏幕内弹跳球
+https://github.com/hankzhuo/react-native-bouncing-ball)
+
 ## 工具
 
 * react-native-snippets(代码提示)