Allow custom constraints on jsonapi_resources routes.

Author: davidstosik

lib/jsonapi/routing_ext.rb

@@ -69,7 +69,8 @@ def jsonapi_resources(*resources, &_block)
           options[:path] = format_route(@resource_type)
 
           if res.resource_key_type == :uuid
-            options[:constraints] = {id: /[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}/}
+            options[:constraints] ||= {}
+            options[:constraints][:id] ||= /[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}/
           end
 
           if options[:except]