ActiveRecord 4.1.0 から inverse_of の指定はいらない？

gem "activerecord", ">= 4.1.0"
require "active_record"

ActiveRecord::Migration.verbose = false
ActiveRecord::Base.establish_connection(:adapter => "sqlite3", :database => ":memory:")
ActiveRecord::Schema.define do
  create_table :users do |t|
  end
  create_table :articles do |t|
    t.belongs_to :user
  end
end

class User < ActiveRecord::Base
  has_many :articles
end

class Article < ActiveRecord::Base
  belongs_to :user
end

user = User.create!
user.object_id                  # => 70337900207200

article = user.articles.create!
article.user.object_id          # => 70337900207200