diff --git a/Gemfile b/Gemfile
index 6669eae..b165f31 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,6 +3,7 @@ source "https://rubygems.org"
 gemspec
 
 group :development do
+  gem "irb"
   gem "bundler"
   gem "rake"
   gem "test-unit"