Embedded has_one returns an array with the key pluralized

lib/active_model/serializer.rb

@@ -101,7 +101,7 @@ module ActiveModel
       if associated_data.respond_to?(:to_ary)
         associated_data.map { |elem| association.build_serializer(elem).serializable_hash }
       else
-        association.build_serializer(associated_data).serializable_hash
+        [association.build_serializer(associated_data).serializable_hash]
       end
     end
 

lib/active_model/serializer/associations.rb

@@ -49,7 +49,7 @@ module ActiveModel
         end
 
         def embedded_key
-          name
+          name.pluralize
         end
       end