title: Ruby & Selenium - how to pass arguments to browser?
body: <p>My search has only turned up answers for Java - <a href="https://stackoverflow.com/questions/30256617/how-can-i-tell-selenium-to-start-firefox-with-certain-commandline-options">this</a> and <a href="https://stackoverflow.com/questions/31721486/how-to-add-phantomjsdriver-command-line-arguments">this</a></p>
  
  <p>The selenium gem doesn't include <code>addCommandLineOptions</code> as far as I can tell, but it does have <code>WebDriver::Remote::Capabilities</code>.</p>
  
  <p>How do I use it to add arguments? I know you pass it as <code>desired_capabilities:</code> to the driver constructor, but in what format?</p>
  
  <p>Unfortunately <a href="http://www.rubydoc.info/gems/selenium-webdriver/0.0.28/Selenium/WebDriver/Remote/Capabilities" rel="nofollow noreferrer">the documentation</a> has been especially useless</p>