安装cocoapods

把镜像更换成淘宝镜像
1、gem sources --remove https://rubygems.org/
2、gem sources -a https://ruby.taobao.org/
3、gem install cocoapods

4、提示error: RPC failed; curl 56 SSLRead() return error -9806
使用一下方式解决
cd ~/.cocoapods/repos
git clone https://github.com/CocoaPods/Specs.git master
pod install
或者
rm -fr ~/.cocoapods/repos/master
pod setup