title: Formtastic - customise blank option in select tag
body: <p>I'm using formtastic to generate a list of options in a select tag (eg. :as => :select) and I want a "blank" option, but this creates an XHTML warning (i.e. trimming empty </p>
  
  <p>Looking at the source, it looks like formtastic is generating:</p>
  
  <pre><code>&lt;option value=""&gt;&lt;/option&gt;
  </code></pre>
  
  <p>Is there a way to customise how formtastic generates blanks options?</p>