Extend Rails Application without change original files

0_custom_extends.rb

# config/initializes/0_custom_extends.rb
# 让 Rails Autoload Path 载入 lib/custom 里面的内容
# 让 lib/custom/uploaders 里面的东西优先级更高
ActiveSupport::Dependencies.autoload_paths.delete("#{Rails.root}/app/uploaders")
ActiveSupport::Dependencies.autoload_paths.delete("#{Rails.root}/app/models")
ActiveSupport::Dependencies.autoload_paths += %W(
  #{Rails.root}/lib/custom/models
  #{Rails.root}/lib/custom/models/hooks
  #{Rails.root}/lib/custom/models/concerns
  #{Rails.root}/app/models
  #{Rails.root}/lib/custom/controllers
  #{Rails.root}/lib/custom/controllers/concerns
  #{Rails.root}/lib/custom/services
  #{Rails.root}/lib/custom/workers
  #{Rails.root}/lib/custom/uploaders
  #{Rails.root}/lib/custom/helpers
  #{Rails.root}/lib/custom
  #{Rails.root}/app/uploaders
)

# === Extend Routes ===
# Prepend routes, add more route
Rails.application.routes.prepend do
  get 'foo' => "you_new_controller#foo"
end

user.rb

# lib/custom/models/user.rb
require_dependency Rails.root.join('app/models/user')

puts "==== Init Custom Features ==="

# === Extend Models ===
User.send(:include, UserExt)

# === Controller ===
ApplicationController.send(:include, ApplicationControllerExt)