title: Change the button label on 'file' upload
body: <p>How to change the button label for 'upload'</p>
  
  <p>I am making upload form like this.</p>
  
  <pre><code> $form = $this-&gt;createFormBuilder($document)
   -&gt;add('file',null,array('label' =&gt; 'send'))
  </code></pre>
  
  <p>it makes a button labeled 'upload documents'</p>
  
  <p>I want to change label to 'send'</p>
  
  <p>How can I change the label of button?</p>