diff --git a/Gemfile b/Gemfile
index 63caecf..82de7d9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,3 +10,4 @@ gem 'fileutils', '>= 1.2.0'
 gem 'rake-compiler'
 gem 'test-unit'
 gem "test-unit-ruby-core"
+gem "rdoc"