diff --git a/docs/Gemfile b/docs/Gemfile
index 1498e641c..c351dde29 100644
--- a/docs/Gemfile
+++ b/docs/Gemfile
@@ -1,4 +1,5 @@
 source "https://rubygems.org"
 
 gem "github-pages", group: :jekyll_plugins
-gem 'wdm', '>= 0.1.0' if Gem.win_platform?
\ No newline at end of file
+gem 'wdm', '>= 0.1.0' if Gem.win_platform?
+gem "webrick"