diff --git a/Gemfile b/Gemfile
index fb0e26773..d79593bee 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,6 +10,7 @@ source "http://rubygems.org"
 
 gem "jekyll"
 gem "rack"
+gem "webrick"
 # If you want to use GitHub Pages, remove the "gem "jekyll"" above and
 # uncomment the line below. To upgrade, run `bundle update github-pages`.
 # gem "github-pages", group: :jekyll_plugins