diff --git a/Gemfile b/Gemfile
index fffdea6..e286627 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,2 +1,6 @@
 source "https://rubygems.org"
+# For now this is a GitHub Pages hosted website.
+#   Ref: https://github.com/Mikaela/mikaela.github.io/issues/153
 gem "github-pages"
+# Required for `bundle exec jekyll serve`
+gem "webrick"
diff --git a/Gemfile.lock b/Gemfile.lock
index 2cca6fa..d865535 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -249,6 +249,7 @@ GEM
       unf_ext
     unf_ext (0.0.8.2)
     unicode-display_width (1.8.0)
+    webrick (1.7.0)
     zeitwerk (2.5.4)
 
 PLATFORMS
@@ -256,6 +257,7 @@ PLATFORMS
 
 DEPENDENCIES
   github-pages
+  webrick
 
 BUNDLED WITH
    2.3.7