diff --git a/Gemfile b/Gemfile
index 33f12afe..2be3a9d5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,5 +5,6 @@ group :test do
   gem "minitest"
   gem "rake"
   gem "rubocop"
+  gem "rubocop-performance"
   gem "safe_yaml"
 end