Add a deprecation DSL

lib/active_model/serializer/adapter/attributes.rb

@@ -1,13 +1,14 @@
-require 'active_model_serializers/adapter/attributes'
-
 module ActiveModel
   class Serializer
     module Adapter
       class Attributes < DelegateClass(ActiveModelSerializers::Adapter::Attributes)
         def initialize(serializer, options = {})
-          warn "Calling deprecated #{self.class.name} (#{__FILE__}) from #{caller[0..2].join(', ')}. Please use #{self.class.name.sub('ActiveModel::Serializer', 'ActiveModelSerializers')}"
           super(ActiveModelSerializers::Adapter::Attributes.new(serializer, options))
         end
+        class << self
+          extend ActiveModelSerializers::Deprecate
+          deprecate :new, 'ActiveModelSerializers::Adapter::Json.'
+        end
       end
     end
   end