diff --git a/Gemfile b/Gemfile
index 672e9e4..66f9337 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,6 +4,11 @@ source "https://rubygems.org"
 
 gemspec
 
-group :test do
-  gem "html-proofer", "~> 5.0"
+gem "html-proofer", "~> 5.0", group: :test
+
+platforms :mingw, :x64_mingw, :mswin, :jruby do
+  gem "tzinfo", ">= 1", "< 3"
+  gem "tzinfo-data"
 end
+
+gem "wdm", "~> 0.1.1", :platforms => [:mingw, :x64_mingw, :mswin]