instance method add_options!

# File railties/lib/rails_generator/generators/applications/app/app_generator.rb, line 119
    def add_options!(opt)
      opt.separator ''
      opt.separator 'Options:'
      opt.on("-r", "--ruby=path", String,
             "Path to the Ruby binary of your choice (otherwise scripts use env, dispatchers current path).",
             "Default: #{DEFAULT_SHEBANG}") { |v| options[:shebang] = v }

      opt.on("-d", "--database=name", String,
            "Preconfigure for selected database (options: #{DATABASES.join('/')}).",
            "Default: #{DEFAULT_DATABASE}") { |v| options[:db] = v }

      opt.on("-f", "--freeze",
            "Freeze Rails in vendor/rails from the gems generating the skeleton",
            "Default: false") { |v| options[:freeze] = v }
    end