title: Behat + BrowserStack
body: <p>I am looking to integrate Behat and BrowserStack. I got the basic functionality set up but I want to enable local tunnling. I have downloaded the required jar to do that. The problem comes when I want to set the "browserstack_tunnel" param. </p>
  
  <p>In the MinkExtenstion/Services/Extention.php I added the following keys to the seliuem2 profile. </p>
  
  <pre><code>booleanNode('browserstack-tunnel')-&gt;end()-&gt;
  booleanNode('browserstack-debug')-&gt;end()-&gt;
  </code></pre>
  
  <p>This is my behat.yml :</p>
  
  <pre><code>default:
   filters:
     tags: "~@todo"
   formatter:
     name: pretty
   parameters:
     snippets: false
  
  extensions:
  
  SilverStripe\BehatExtension\MinkExtension:
    # Adjust "base_url" to your own website URL.
    # Can be set via environment variables or _ss_environment.php/$_FILE_TO_URL_MAPPING as well.
    # 
    # base_url:  http://localhost/
  
    # TODO Dynamically set through LocatorProcessor
    files_path: %behat.paths.base%/framework/tests/behat/features/files/
    default_session: selenium2
    javascript_session: selenium2
    goutte: ~
    selenium2:
  browserstack:
    extensions:
      SilverStripe\BehatExtension\MinkExtension:
        selenium2:
          browser: firefox
          # Add your own username and API token here
          wd_host: http://&lt;username&gt;:&lt;key&gt;@hub.browserstack.com/wd/hub
          browserstack-tunnel: true
  
      SilverStripe\BehatExtension\Extension: ~
  </code></pre>