class Rails::Command::ServerCommand

def rack_server_suggestion(server)
  if server.nil?
    <<~MSG
      Could not find a server gem. Maybe you need to add one to the Gemfile?
        gem "#{RECOMMENDED_SERVER}"
      Run `#{executable} --help` for more options.
    MSG
  elsif server.in?(RACK_HANDLER_GEMS)
    <<~MSG
      Could not load server "#{server}". Maybe you need to the add it to the Gemfile?
        gem "#{server}"
      Run `#{executable} --help` for more options.
    MSG
  else
    error = CorrectableNameError.new("Could not find server '#{server}'.", server, RACK_HANDLERS)
    <<~MSG
      #{error.detailed_message}
      Run `#{executable} --help` for more options.
    MSG
  end
end