diff --git a/Gemfile b/Gemfile
index 4788fa6..680489c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
 
 # gem "rails"
 gem "tzinfo-data", :install_if => Gem.win_platform?
-gem "wdm", "~> 0.1.1", :install_if => Gem.win_platform?
+gem "wdm", "~> 0.2.0", :install_if => Gem.win_platform?
 gem "github-pages", "~> 226"
 
 gem "webrick", "~> 1.9"
diff --git a/Gemfile.lock b/Gemfile.lock
index 8efd824..ab693b6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -255,7 +255,7 @@ GEM
     unf_ext (0.0.8.2)
     unicode-display_width (1.8.0)
     uri (1.1.1)
-    wdm (0.1.1)
+    wdm (0.2.0)
     webrick (1.9.2)
 
 PLATFORMS
@@ -265,7 +265,7 @@ PLATFORMS
 DEPENDENCIES
   github-pages (~> 226)
   tzinfo-data
-  wdm (~> 0.1.1)
+  wdm (~> 0.2.0)
   webrick (~> 1.9)
 
 BUNDLED WITH