diff --git a/Gemfile b/Gemfile
index 88ae4bc4e3..1dcc4fedbe 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,6 +2,8 @@ source 'https://rubygems.org/'
 
 gemspec
 
+gem "webrick", git: "https://github.com/ruby/webrick"
+
 local_gemfile = File.join(File.dirname(__FILE__), "Gemfile.local")
 if File.exist?(local_gemfile)
   puts "Loading Gemfile.local ..." if $DEBUG # `ruby -d` or `bundle -v`