Create custom webdriver.rb

require 'selenium-webdriver'
require 'selenium/webdriver/remote/http/persistent'
http_client = ::Selenium::WebDriver::Remote::Http::Persistent.new
url = "http://#{ENV["SAUCE_USERNAME"]}:#{ENV["SAUCE_ACCESS_KEY"]}@ondemand.saucelabs.com:80/wd/hub"
capabilities = Selenium::WebDriver::Remote::Capabilities.safari
capabilities.platform = 'OS X 10.6'
capabilities.version = '5'
Capybara.register_driver :remote_browser do |app|
Capybara::Selenium::Driver.new(app,
                              :browser => :remote, :url => url,
                              :desired_capabilities => capabilities,
                              :http_client => http_client)
                              end
end

Capybara.default_driver = :remote_browser
Capybara.javascript_driver = :remote_browser