Up to date example for Selenium

[posva]

Hello, I noticed the example for Selenium (https://nightwatchjs.org/gettingstarted/configuration/#selenium-example-configuration) is out of date as some options moved around like the selenium option being at the root level.

I have been unable to run tests on Firefox because I get the GeckoDriver not found error even though the package is installed and it is referenced in the selenium configuration:

  selenium: {
    start_process: true,
    start_session: true,
    host: '127.0.0.1',
    port: 4444,
    server_path: require('selenium-server').path,
    cli_args: {
      'webdriver.chrome.driver': require('chromedriver').path,
      'webdriver.gecko.driver': require('geckodriver').path,
    },
  },

  webdriver: {
    start_process: false,
  },

  test_settings: {
    firefox: {
      selenium_port: 4444,
      selenium_host: '127.0.0.1',
      desiredCapabilities: {
        browserName: 'firefox',
      },
    },
  },