CocoaPods 的介绍、安装、使用和原理:https://www.jianshu.com/p/3086df14ed08
使用CocoaPods是怎么把三方库下载到本地的?https://www.jianshu.com/p/20c20fc6db7a
cocoapods,pod repo update 快速更新https://www.jianshu.com/p/1d058d224cad
解决CocoaPods慢的方案(gem和pod repo换源)https://www.jianshu.com/p/c84c9a61e9fe