diff --git a/Gemfile b/Gemfile
index eeb1c593d4..d0ab326567 100644
--- a/Gemfile
+++ b/Gemfile
@@ -16,3 +16,5 @@ gem "rubocop", "~> 0.58.0"
 if %w(2.2.7 2.2.8 2.2.9 2.2.10 2.3.4 2.4.1).include? RUBY_VERSION
   gem "stopgap_13632", "~> 1.0", :platforms => ["mri", "mingw", "x64_mingw"]
 end
+
+gem 'm'