rename simple adapter to json

lib/active_model/serializer/adapter.rb

@@ -2,7 +2,7 @@ module ActiveModel
   class Serializer
     class Adapter
       extend ActiveSupport::Autoload
-      autoload :SimpleAdapter
+      autoload :JsonAdapter
       autoload :NullAdapter
       autoload :JsonApiAdapter
 

lib/active_model/serializer/adapter/json_adapter.rb

@@ -1,7 +1,7 @@
 module ActiveModel
   class Serializer
     class Adapter
-      class SimpleAdapter < Adapter
+      class JsonAdapter < Adapter
         def serializable_hash(options = {})
           serializer.attributes.each_with_object({}) do |(attr, value), h|
             h[attr] = value

lib/active_model/serializer/configuration.rb

@@ -6,7 +6,7 @@ module ActiveModel
 
       included do |base|
         base.config.array_serializer = ActiveModel::Serializer::ArraySerializer
-        base.config.adapter = :simple
+        base.config.adapter = :json
       end
     end
   end

lib/active_model_serializers.rb

@@ -1,7 +1,6 @@
 require "active_model"
 require "active_model/serializer/version"
 require "active_model/serializer"
-require "active_model/serializer/adapter/simple_adapter"
 
 begin
   require 'action_controller'