class Puma::Configuration

def config_files
  files = @options.all_of(:config_files)
  return [] if files == ['-']
  return files if files.any?
  first_default_file = %W(config/puma/#{@options[:environment]}.rb config/puma.rb).find do |f|
    File.exist?(f)
  end
  [first_default_file]
end