curl \
--verbose \
--request OPTIONS \
http://localhost:3001/api/configuration/visitor \
--header 'Origin: http://localhost:9292' \
--header 'Access-Control-Request-Headers: Origin, Accept, Content-Type' \
--header 'Access-Control-Request-Method: GET' 


# http://nils-blum-oeste.net/cors-api-with-oauth2-authentication-using-rails-and-angularjs/#.UQJeLkp4ZyE

# http://blog.carbonfive.com/2012/02/27/supporting-cross-domain-ajax-in-rails-using-jsonp-and-cors/