def set_browser_id
      until cookies[:browser_id]
        proposed_browser_id = SecureRandom.uuid
        unless Session.where(:browser_id => proposed_browser_id).exists?
          cookies[:browser_id] = {:value => proposed_browser_id, :expires => 20.years.from_now}
        end
      end
    end
def set_browser_id
      until cookies[:browser_id]
        proposed_browser_id = SecureRandom.uuid
        unless Session.where(:browser_id => proposed_browser_id).exists?
          cookies[:browser_id] = {:value => proposed_browser_id, :expires => 20.years.from_now}
        end
      end
    end
Set a random browser ID for this browser.