petrarca.gemspec in petrarca-0.3.0 vs petrarca.gemspec in petrarca-0.4.0

@@ -38,6 +38,7 @@
   spec.require_paths = ["lib"]
 
   spec.add_development_dependency "bundler", "~> 2.0"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", ">= 3.0.0"
+  spec.add_development_dependency "nokogiri"
 end