title: Does NightwatchJS support running tests by tags
body: <p>I see that there exists a "tags" support with NightwatchJS , as in</p>
  
  <p><a href="https://github.com/beatfactor/nightwatch/blob/master/examples/tests/github.js#L2" rel="nofollow">https://github.com/beatfactor/nightwatch/blob/master/examples/tests/github.js#L2</a></p>
  
  <p>But could not see much documentation about how the "tags" could be used.</p>
  
  <p>Neither in nightwatch --help</p>
  
  <p>Is there a facility to run the tests based on these tags ?</p>
  
  <p>For example,  run all tests with tag "sms" but exclude all with tag "mms" ?</p>