A Rails app generator tuned my common needs

clever-rails.rb

#!/usr/bin/env ruby

require 'rails/generators'
require 'rails/generators/rails/app/app_generator'
require "active_support/core_ext/string/strip"

class CleverAppGenerator < Rails::Generators::AppGenerator
  class_option :skip_bundle,     default: true
  class_option :database,        default: "postgresql"
  class_option :skip_test_unit,  default: true, hide: true

  def self.source_root(path=nil)
    Rails::Generators::AppGenerator.source_root(path)
  end

  protected
  def self.banner
    "./clever-rails #{self.arguments.map(&:usage).join(' ')} [options]"
  end

  def app_secret
    "APP_SECRET"
  end
end

class AppBuilder < Rails::AppBuilder
  def readme
    copy_file "README", "README.md"
  end

  def gitignore
    super
    @generator.append_file '.gitignore',  <<-DOC.strip_heredoc
      /.env
      /config/database.yml
    DOC
  end

  def database_yml
    template "config/databases/#{options[:database]}.yml", "config/database.example.yml"
    template "config/databases/#{options[:database]}.yml", "config/database.yml"
  end

  def lib
    empty_directory "lib"
    empty_directory_with_gitkeep "lib/tasks"
    empty_directory_with_gitkeep "lib/assets"
  end

  def public_directory
    super
    remove_file "public/index.html"
    remove_file 'app/assets/images/rails.png'
    empty_directory_with_gitkeep "app/assets/images"
  end

  def gemfile
    super
    @generator.append_file 'Gemfile',  <<-DOC.strip_heredoc
      gem "bootstrap-sass"
      gem "pjax_rails"

      gem "thin"
      gem "foreman"

      group :development, :test do
        gem "rspec-rails"
      end
    DOC
  end

  def rspec
    say("Installing rspec from generator", :yellow)
    system('rails generate rspec:install')
  end

  def rake
    say("Creating and migrating initial database", :yellow)
    system "rake db:create db:migrate"
  end

  def leftovers
    foreman_setup
    app_secret_from_env
    swap_pg_username
    update_application_config
    update_boot_rb
    rspec
    bootstrap_sass
    rake
  end

  def foreman_setup
    create_file 'Procfile', <<-DOC.strip_heredoc
    web: bundle exec rails server thin -p $PORT
    DOC

    create_file '.env', <<-DOC.strip_heredoc
    PORT=3000
    RAILS_SECRET_TOKEN=#{SecureRandom.hex(64)}
    DOC
  end

  def app_secret_from_env
    gsub_file("config/initializers/secret_token.rb", "'APP_SECRET'", "ENV['RAILS_SECRET_TOKEN']")
  end

  def swap_pg_username
    %w[config/database.yml config/database.example.yml].each do |file|
      gsub_file(file, /^  username: .*$/, '  username: postgres')
    end
  end

  def update_application_config
    inject_into_class("config/application.rb", "Application") do
      <<-DOC
    config.assets.initialize_on_precompile = false

    config.autoload_paths += %W(\#{config.root}/lib)

    config.i18n.load_path += Dir[Rails.root.join('config', 'locales', '**', '*.{rb,yml}')]

    config.generators do |g|
      g.view_specs    false
      g.routing_specs false
      g.stylesheets   false
      g.javascripts   false
      g.helper        false
    end
      DOC
    end
  end

  def update_boot_rb
    prepend_to_file("config/boot.rb") do
      <<-DOC.strip_heredoc
      # Don't buffer stdout
      $stdout.sync = true
      DOC
    end
  end

  def bootstrap_sass
    gsub_file("app/assets/javascripts/application.js", "//= require_tree .") do
      <<-DOC.strip_heredoc
      //= require bootstrap
      //= require_tree .
      DOC
    end

    remove_file("app/assets/stylesheets/application.css")
    create_file("app/assets/stylesheets/application.sass") do
      '@import "bootstrap";'
    end
  end
end

CleverAppGenerator.start