Added some documentation for attributes

README.rdoc

@@ -75,6 +75,14 @@ What's left at this point, is to wrap it all up in a controller and point the in
     end
   end
 
+If are using saml:AttributeStatement to transfare metadata, like the user name, you can access all the attributes through response.attributes. It
+contains all the saml:AttributeStatement with its 'Name' as a indifferent key and the one saml:AttributeValue as value.
+
+  response          = Onelogin::Saml::Response.new(params[:SAMLResponse])
+  response.settings = saml_settings
+
+  response.attributes[:username]
+
 
 = Full Example