less strict Rails version

Author: Francesco Rodriguez

actionpack-action_caching.gemspec

@@ -17,5 +17,5 @@ Gem::Specification.new do |gem|
   gem.add_dependency 'actionpack', '>= 4.0.0.beta', '< 5.0'
 
   gem.add_development_dependency 'mocha'
-  gem.add_development_dependency 'activerecord', '>= 4.0.0.beta', '< 5.0'
+  gem.add_development_dependency 'activerecord', '>= 4.0.0.beta', '< 5'
 end