acme-client.gemspec in acme-client-0.3.0 vs acme-client.gemspec in acme-client-0.3.1

@@ -13,9 +13,11 @@
   spec.license       = 'MIT'
 
   spec.files         = `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
   spec.require_paths = ['lib']
 
+  spec.required_ruby_version = '>= 2.1.0'
+
   spec.add_development_dependency 'bundler', '~> 1.6', '>= 1.6.9'
   spec.add_development_dependency 'rake', '~> 10.0'
   spec.add_development_dependency 'rspec', '~> 3.3', '>= 3.3.0'
   spec.add_development_dependency 'vcr', '~> 2.9', '>= 2.9.3'
   spec.add_development_dependency 'webmock', '~> 1.21', '>= 1.21.0'