Configuration to use unicorn with capybara

capybara_config.rb

Capybara.register_server :unicorn do |app, port, host, **options|
  rackup_opts = Unicorn::Configurator::RACKUP
  rackup_opts[:host] = host
  rackup_opts[:port] = port
  rackup_opts[:set_listener] = true
  server = Unicorn::HttpServer.new(app, rackup_opts[:options])
  server.logger.level = :warn
  at_exit do
    trap(:CHLD, nil)
    server.stop(false)
  end
  server.start.join
end