title: How do I add an icon inside a text_field_tag
body: <p>I'm using Rails 4 and Font Awesome (sass). I would like to add an icon to the left side of the search function, just like on Stack Overflow. This is my code for the search function.</p>
  
  <p>index.html.erb</p>
  
  <pre><code>&lt;%= form_tag products_path, method: :get do %&gt;
    &lt;%= text_field_tag :query, params[:query], placeholder: "Search..." %&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>How would I go about to add:</p>
  
  <pre><code>&lt;%= icon 'search' %&gt; 
  </code></pre>
  
  <p>into my text_field_tag so that I can also style the icon? Thanks.</p>