Single-file Rails application

app.ru

# Run with:
# $ rackup app.ru

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'
  gem 'rails', '~> 7.0.5'
  gem 'puma'
end

require 'action_controller/railtie'

class App < Rails::Application
  config.root = __dir__
  config.consider_all_requests_local = true
  config.secret_key_base = SecureRandom.hex
  config.eager_load = false

  routes.append do
    root to: 'welcome#index'
  end
end

class WelcomeController < ActionController::Base
  def index
    render inline: 'Hello'
  end
end

App.initialize!

run App