Scope as_json patch to ActiveResource::Base instead of ActiveModel.

lib/shopify_api/json_format.rb

@@ -6,6 +6,16 @@ module ActiveResource
       
       same.send("to_#{self.class.format.extension}", options)
     end
+
+    def as_json(options = nil)
+      root = options[:root] if options.try(:key?, :root)
+      if include_root_in_json
+        root = self.class.model_name.element if root == true
+        { root => serializable_hash(options) }
+      else
+        serializable_hash(options)
+      end
+    end
   end
 
   module Formats
@@ -21,19 +31,3 @@ module ActiveResource
     end
   end
 end
-
-module ActiveModel
-  module Serializers
-    module JSON
-      def as_json(options = nil)
-        root = options[:root] if options.try(:key?, :root)
-        if include_root_in_json
-          root = self.class.model_name.element if root == true
-          { root => serializable_hash(options) }
-        else
-          serializable_hash(options)
-        end
-      end
-    end
-  end
-end