Gemfile in PageRankr-3.0.0 vs Gemfile in PageRankr-3.0.1

@@ -1,5 +1,7 @@
 source :gemcutter
 
 gemspec
 
-gem 'ruby-debug19', :require => 'ruby-debug'
+group :development do
+  gem 'ruby-debug19', :require => 'ruby-debug', :platforms => :mri_19
+end
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