Gemfile in gemdiff-0.4.0 vs Gemfile in gemdiff-0.4.1

@@ -1,7 +1,14 @@
 source 'https://rubygems.org'
+
+platform :mri_21 do
+  unless ENV['TRAVIS']
+    gem "pry-byebug", "~> 1.3"
+  end
+end
+
 gemspec