This is a Rails Application Generator that I commonly use. There are a lot of questions that prompt the user for feedback, and as I continue to develop more gems or Rails generators may be changed. For now it depends on the gem hub (install by running gem install hub).

builder.rb

class AppBuilder < Rails::AppBuilder
  # Checks to make sure that hub is installed before continuing
  def rakefile
    if `which hub`.strip == ""
      say "hub", "Please install hub. https://github.com/defunkt/hub"
      exit 1
    end
  end

  # Makes the readme use Markdown and pre-populates it with basic information
  def readme
    @app_name = File.basename(File.expand_path("."))
    create_file "README.md", "#{app_name} App\n======================\nDo this first\n-------\n\t$ bundle exec rake db:migrate"
  end

  # Asks the user basic questions and adds commonly used gems
  def gemfile
    template "Gemfile"
    @generator.gem 'unicorn'
    @generator.gem 'newrelic_rpm'
    @generator.gem 'foreman', group: [:development, :test]
    @generator.gem 'sqlite3', group: [:development, :test]
    @generator.gem 'pg', group: [:production]

    if yes? "Do you want to include the better_errors gem for debugging?"
      @generator.gem 'better_errors'
      @generator.gem 'binding_of_caller'
    end
  end
  
  # Sets up testing based on RSpec and Capybara
  def test
    if yes? "Do you want to use RSpec to testing?"
      rspec = true
      @generator.gem 'rspec-rails', group: [:test, :development]
    end
    if yes? "Do you want to include Capybara for testing?"
      capy = true
      @generator.gem 'capybara', group: [:test, :development]
      @generator.gem 'launchy', group: [:test, :development]
    end
    if yes? "Do you want to use Guard to monitor and proivde live changes?"
      guard = true
      @generator.gem 'rb-fsevent', :require => false if RUBY_PLATFORM =~ /darwin/i
      @generator.gem 'guard-rspec'
      if yes? "Use livereload to refresh CSS live with Guard?"
        reload = true
        @generator.gem 'guard-livereload'
      end
    end
      run "bundle install"
      generate 'rspec:install' if rspec
      generate 'guard init livereload' if reload
      generate 'guard init rspec' if guard
  end
  
  # This is where all the extraneous information goes
  def leftovers
    # Generate a root controller
    if yes? "Do you want to generate a root controller?"
      name = ask("What should it be called?").underscore
      generate :controller, "#{name} index"
      route "root to: '#{name}\#index'"
      remove_file "public/index.html"
    end

    # Initialize Git and ignore files
    git :init
    append_file ".gitignore", "public/assets/\n*~\n.project\n.DS_Store\n.idea\n*.sublime-project\n*.sublime-workspace"
    # Add line into config/application.rb
    insert_into_file "config/application.rb", "config.assets.initialize_on_precompile = false", :after => "config.assets.version = '1.0'\n"

    # Set config assets compile to true
    gsub_file "config/environments/production.rb", "config.assets.compile = false", "config.assets.compile = true"

    # Add the rack deflater for Gzip and compression
    insert_into_file 'config.ru', "use Rack::Deflater\n", :before => "run"

    # Remove the public index.html
    remove_file 'public/index.html'

    # Create the procfile
    create_file "Procfile", "web: bundle exec unicorn -p $PORT -c ./config/unicorn.rb\n# db: postgres -D /usr/local/var/postgres"
    # Create the unicorn.rb file used specifically for Heroku apps and the Unicorn gem
    create_file "config/unicorn.rb", "worker_processes 3\ntimeout 30\npreload_app true\nafter_fork do |server, worker|\ndefined?(ActiveRecord::Base) and\n\tActiveRecord::Base.establish_connection\nend"
    # Curl in the newrelic yaml file (there is a bug with Ruby's open url so curl was used instead)
    run 'curl -O https://raw.github.com/newrelic/rpm/master/newrelic.yml'
    run 'cp newrelic.yml config/newrelic.yml && rm newrelic.yml'
    # Add inital commit
    git add: ".", commit: "-m 'initial commit'"

    # Add a Git repository if it exists
    if yes? "Do you want to create a GitHub Repository?"
      github_private = yes? "Create a private repository?"

      tried_create_already = false
      while (@git_uri = `git config remote.origin.url`.strip) && @git_uri.size == 0
        if tried_create_already
          @repo_name = ask_wizard "Repository #{@repo_name} already exists. What project name?"
        else
          @repo_name = File.basename(File.expand_path("."))
        end
        if github_private
          run "hub create #{@repo_name} -p"
        else
          run "hub create #{@repo_name}"
        end
        tried_create_already = true
      end

      # Add Heroku app
      if yes? "Add Heroku sites?"
        @repo_name = File.basename(File.expand_path("."))
        run "heroku apps:create #{@repo_name}"
        run "heroku apps:create #{@repo_name}-staging"
        run "git remote add staging git@heroku.com:#{@repo_name}-staging"
      end

    end

  end
end