use respond_to_missing? not respond_to?

since Ruby 1.9.2, about 12 years ago, you're supposed to define respond_to_missing? if you also define method_missing. there's more explanation in this blog post by a ruby committer in 2010:

http://blog.marc-andre.ca/2010/11/15/methodmissing-politely/

Author: indirect

elasticsearch-model/lib/elasticsearch/model/proxy.rb

@@ -123,7 +123,7 @@ def method_missing(method_name, *args, **kwargs, &block)
 
         # Respond to methods from `@target`
         #
-        def respond_to?(method_name, include_private = false)
+        def respond_to_missing?(method_name, include_private = false)
           target.respond_to?(method_name) || super
         end