rails gしたら`method_missing': undefined method `load_defaults' ってエラー出た

環境

CentOS7
Ruby 2.3.1
Rails 5.1.2

Gemfile

source 'https://rubygems.org'

gem 'rails', '5.0.3'
gem 'puma',         '3.9.1'
gem 'bootstrap-sass', '3.3.6'
gem 'sass-rails',   '5.0.6'
gem 'uglifier',     '3.2.0'
gem 'coffee-rails', '4.2.2'
gem 'jquery-rails', '4.3.1'
gem 'turbolinks',   '5.0.1'
gem 'jbuilder',     '2.6.1'
gem 'therubyracer'

group :development, :test do
  gem 'sqlite3', '1.3.13'
  gem 'byebug',  '9.0.6', platform: :mri
end

group :development do
  gem 'web-console',           '3.5.1'
  gem 'listen',                '3.0.8'
end

group :test do
  gem 'rails-controller-testing', '1.0.2'
  gem 'minitest-reporters',       '1.1.14'
end

group :production do
  gem 'pg', '0.18.4'
end

CentOS環境にはRails 5.1〜, GemfileにはRails 5.0〜を指定してbundle update, bundle installした。
その結果rails gした際に以下のエラー発生。

# webyaji=筆者の開発アプリ
[vagrant@localhost webyaji]$ rails g model test
/usr/local/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.3/lib/rails/railtie/configuration.rb:95:in `method_missing': undefined method `load_defaults' for #<Rails::Application::Configuration:0x007fa562795108> (NoMethodError)
	from /home/vagrant/app/webyaji/config/application.rb:12:in `<class:Application>'
	from /home/vagrant/app/webyaji/config/application.rb:10:in `<module:Webyaji>'
	from /home/vagrant/app/webyaji/config/application.rb:9:in `<top (required)>'
	from /usr/local/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.3/lib/rails/commands/commands_tasks.rb:156:in `require'
	from /usr/local/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.3/lib/rails/commands/commands_tasks.rb:156:in `require_application_and_environment!'
	from /usr/local/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.3/lib/rails/commands/commands_tasks.rb:143:in `generate_or_destroy'
	from /usr/local/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.3/lib/rails/commands/commands_tasks.rb:60:in `generate'
	from /usr/local/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.3/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
	from /usr/local/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.3/lib/rails/commands.rb:18:in `<top (required)>'
	from bin/rails:9:in `require'
	from bin/rails:9:in `<main>'

たぶんload_defaultsとかいうメソッドしらねーよって怒られてる。
一時間ほどハマったが調べていくとload_defaultsがRails5.1系から使えるようになったメソッドと判明。

# config/application.rb
require_relative 'boot'

require 'rails/all'

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module Webyaji
  class Application < Rails::Application
    # Initialize configuration defaults for originally generated Rails version.
    - config.load_defaults 5.1
    + # config.load_defaults 5.1

    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration should go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded.
  end
end

コメントアウト後、再度rails gして大丈夫になったことを確認。

[vagrant@localhost webyaji]$ rails g model test
Expected string default value for '--jbuilder'; got true (boolean)
      invoke  active_record
      create    db/migrate/20170725131230_create_tests.rb
      create    app/models/test.rb
      invoke    test_unit
      create      test/models/test_test.rb
      create      test/fixtures/tests.yml

参考

Rails 5.1で追加されたconfigまとめ | 日々雑記