How to select your custom profile in your env.rb

gistfile1.rb

Capybara.register_driver :firefox_custom do |app|
  require 'selenium/webdriver'
  profile_path = "/path/to/prototype_profile"
  profile = Selenium::WebDriver::Firefox::Profile.new(profile_path)
  driver = Capybara::Driver::Selenium.new(app, :profile => profile)

  driver
end

# And set the default driver to our new one:

Capybara.default_driver = :firefox_custom