ruby-mext.gemspec in ruby-mext-0.21.5 vs ruby-mext.gemspec in ruby-mext-0.21.6

@@ -34,8 +34,8 @@
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rake'
   spec.add_development_dependency 'rspec'
   spec.add_development_dependency 'rdoc'
   spec.add_development_dependency 'byebug'
-  spec.add_development_dependency 'matplotlib'
+  spec.add_development_dependency 'gruff'
 
 end