cocoapods 在 Mac10.11 遇到如果下问题/System/Library/Frameworks//Versions/2.0/usr/lib/ruby/2.0.0/universal-darwin15/:213: warning: Insecure world writable dir /usr/local/bin in PATH, mode 040777ERROR: While executing gem ... (Errno::EPERM) Operation not permitted - /usr/bin/pod
解决：sudo gem install -n /usr/local/bin cocoapods