minimal rails app

rails

require 'rails'
require 'logger'

APP_PATH = 'rails'
root = File.expand_path("#{__dir__}/..")
config = Rails::Application::Configuration.new
config.root = root
app = Class.new(Struct.new(:root, :config)) do
  def call _
    [200, {}, ["OK\n"]]
  end
end.new(root, config)
Rails.application = app
Rails.logger = Logger.new(File.open(IO::NULL))

require 'rails/commands'