Mac系统到macOS High Sierra后pod出现问题

最近在更新Mac系统到macOS High Sierra后，pod install 出现下面提示：

  -bash: /usr/local/bin/pod: /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby: bad interpreter: No such file or directory

解决办法：

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