diff --git a/docs/Gemfile b/docs/Gemfile
index dc676cd..3294314 100644
--- a/docs/Gemfile
+++ b/docs/Gemfile
@@ -5,3 +5,5 @@ source "https://rubygems.org"
 git_source(:github) {|repo_name| "https://github.com/#{repo_name}.git" }
 
 gem 'github-pages', group: :jekyll_plugins
+
+gem "webrick", "~> 1.8"
diff --git a/docs/Gemfile.lock b/docs/Gemfile.lock
index f8e5b80..59260ac 100644
--- a/docs/Gemfile.lock
+++ b/docs/Gemfile.lock
@@ -263,6 +263,7 @@ GEM
     unf_ext (0.0.9.1)
     unicode-display_width (1.8.0)
     uri (0.13.0)
+    webrick (1.8.1)
 
 PLATFORMS
   arm64-darwin-21
@@ -272,6 +273,7 @@ PLATFORMS
 
 DEPENDENCIES
   github-pages
+  webrick (~> 1.8)
 
 BUNDLED WITH
    2.3.11