diff --git a/Gemfile b/Gemfile
index 66f71ba..7a983bf 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,4 @@
 source "https://rubygems.org"
 gem 'tzinfo-data'
+gem 'wdm', '>= 0.1.0' if Gem.win_platform?
 gem "github-pages", group: :jekyll_plugins