title: Using autofocus and text_field form helpers in Rails
body: <p>How do I include the '<code>autofocus</code>' attribute on an <code>HTML5</code> form using the <code>text_field</code> form helper in <code>Rails</code>?</p>
  
  <p>e.g. <code>&lt;%= f.text_field :email %&gt;</code>
  Where does autofocus go?</p>
  
  <p>Thanks</p>