title: bootstrap icon in a submit_tag rails form
body: <p>I have this form:</p>
  
  <pre><code>&lt;%= form_tag(user_pages_path(current_user), :method =&gt; "get") do %&gt;
    &lt;%= text_field_tag :update, 'yes', type: "hidden"  %&gt;
    &lt;%= submit_tag "Update list", :class =&gt; "btn btn-default" %&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>and I would like to include an icon in the button. I'm using bootstrap, so i must include this code:</p>
  
  <pre><code>&lt;i class=" icon-repeat"&gt;&lt;/i&gt;
  </code></pre>
  
  <p>¿Any idea about how to include this code in the form button?</p>