Errno::EACCES: Permission denied @ rb_sysopen -/Users/USERNAME/DIR/DIR/DIR/docs.scala-lang/vendor/bundle/ruby/2.4.0/gems/nokogiri-1.8.4/.autotestAn error occurred while installing nokogiri (1.8.4), and Bundler cannotcontinue.Make sure that `gem install nokogiri -v '1.8.4' --source 'https://rubygems.org/'` succeedsbefore bundling.

yifans-MacBook-Pro:docs.scala-lang yifanxing$ bundle exec jekyll serve -ICould not find gem 'jekyll-redirect-from' in any of the gem sources listed in your Gemfile.Run `bundle install` to install missing gems.yifans-MacBook-Pro:docs.scala-lang yifanxing$ bundle installFetching gem metadata from https://rubygems.org/...........Fetching gem metadata from https://rubygems.org/.Resolving dependencies...Using concurrent-ruby 1.0.5Using i18n 0.9.5Using minitest 5.11.3Using thread_safe 0.3.6Using tzinfo 1.2.5Using activesupport 5.2.1Using public_suffix 3.0.3Using addressable 2.5.2Using bundler 1.16.5Using colorator 1.1.0Using colorize 0.8.1Using eventmachine 1.2.7Using http_parser.rb 0.6.0Using em-websocket 0.5.1Using ffi 1.9.25Using ethon 0.11.0Using forwardable-extended 2.6.0Using mercenary 0.3.6Using mini_portile2 2.3.0Fetching nokogiri 1.8.4Installing nokogiri 1.8.4 with native extensions**Errno::EACCES: Permission denied @ rb_sysopen -/Users/USERNAME/DIR/DIR/DIR/docs.scala-lang/vendor/bundle/ruby/2.4.0/gems/nokogiri-1.8.4/.autotestAn error occurred while installing nokogiri (1.8.4), and Bundler cannotcontinue.Make sure that `gem install nokogiri -v '1.8.4' --source 'https://rubygems.org/'` succeedsbefore bundling.**In Gemfile:  html-proofer was resolved to 3.9.2, which depends on    nokogiriyifans-MacBook-Pro:docs.scala-lang yifanxing$ **gem install nokogiri -v '1.8.4' --source** 'https://rubygems.org/'Building native extensions. This could take a while.../Users/yifanxing/.rvm/rubies/ruby-2.4.0/lib/ruby/site_ruby/2.4.0/rubygems/ext/builder.rb:76: warning: Insecure world writable dir /Users/USERNAME/DIR/DIR in PATH, mode 040777Successfully installed nokogiri-1.8.4Parsing documentation for nokogiri-1.8.4Done installing documentation for nokogiri after 7 seconds1 gem installedyifans-MacBook-Pro:docs.scala-lang yifanxing$