title: Configure Capybara to use Marionette WebDriver for Firefox
body: <p>With Marionette replacing FirefoxDriver, I need to configure my tests to run it. 
  I've downloaded the binary but I can't seem to get my Capybara driver registration configured to actually use Marionette.</p>
  
  <pre><code>Capybara.register_driver :selenium_firefox do |app|
    capabilities = Selenium::WebDriver::Remote::Capabilities.firefox
    capabilities["firefox_binary"] = 'path/to/marionette/renamed/to/wires'
    Capybara::Selenium::Driver.new(app, browser: :firefox, desired_capabilities: capabilities)
  end
  </code></pre>
  
  <p>When I start a test though, I just get the initial page of FF just like I would trying to run it without marionette.</p>