title: Enabling Eslint on typescript files
body: <p>On webstorm eslint setting, there is an "extra eslint options" field.
  In this, I added: </p>
  
  <pre><code>--ext .ts
  </code></pre>
  
  <p>from the eslint <a href="http://eslint.org/docs/user-guide/command-line-interface#ext" rel="noreferrer">documentation</a> which is supposed to allow eslint to work on custom file extension, in this case .ts files.
  This does nothing. Is my syntax wrong ? Anyway to enable Eslint on .ts files, maybe from the .eslintrc file ?</p>