Fix support for rails 5 without breaking previous ruby version support

apivore.gemspec

@@ -18,13 +18,21 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'rspec', '~> 3'
   s.add_runtime_dependency 'rspec-expectations', '~> 3.1'
   s.add_runtime_dependency 'rspec-mocks', '~> 3.1'
-  s.add_runtime_dependency 'actionpack', '>= 4', '< 6'
   s.add_runtime_dependency 'hashie', '~> 3.3'
   s.add_development_dependency 'pry', '~> 0'
   s.add_development_dependency 'rake', '~> 10.3'
   s.add_development_dependency 'rspec-rails', '~> 3'
   s.add_development_dependency 'activesupport', '>= 4', '< 6'
 
+  # Rails 5 stopped support for ruby < 2.2.2
+  # Hack to support currently suported ruby versions
+  # TODO: remove and explicitly require ruby 2.2.2 as min version in version 2 of apivore
+  if RUBY_VERSION >= '2.2.2'
+    s.add_runtime_dependency 'actionpack', '>= 4', '< 6'
+  else
+    s.add_runtime_dependency 'actionpack', '< 5'
+  end
+
   if RUBY_VERSION >= '2.2.0'
     s.add_development_dependency 'test-unit', '~> 3'
   end