title: Send file to server in grails 3.0.0.1
body: <p>I'm doing some test with grails 3.0.0.M1 and I have a form that sends a file to server using :</p>
  
  <p>In view: </p>
  
  <pre><code>&lt;g:uploadForm controller="file" action="upload"&gt;
      &lt;input type="file" name="file" /&gt;
      &lt;input type="submit" value="send"/&gt;
  &lt;/g:uploadForm&gt;
  </code></pre>
  
  <p>and In the controller I have:</p>
  
  <pre><code>def file() {
      def f = request.getFile("file")
      //....some code  
  }
  </code></pre>
  
  <p>With f I have a NullPointerException that is to say the server don't receive the file from the view.
  How how I can fix it?
  Thanks!</p>