CocoaPods版本的更新

sudo gem install cocoapods这一步在os x10.11会出现错误

Updating rubygems-update
ERROR:  While executing gem ... (Errno::EPERM)
    Operation not permitted - /usr/bin/update_rubygems

参考下面方法解决

http://stackoverflow.com/questions/30812777/cannot-install-cocoa-pods-after-uninstalling-results-in-error/30851030#30851030/

sudo gem install -n /usr/local/bin cocoapods

另外附上CocoaPods官网：

https://cocoapods.org/