diff --git a/Gemfile b/Gemfile
index ffc2ab1..20de0d5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -16,3 +16,5 @@ end
 
 gem 'unicode', '~> 0.4', :platforms => [:mri, :rbx, :mswin, :mingw]
 gem 'ritex', '~> 1.0.1'
+
+gem 'rubysl', '~> 2.0', :platforms => :rbx