title: simple_form gem and specifying possible values of minute input
body: <p>I use simple_form gem
  In my view.html.haml i have code</p>
  
  <pre><code>f.input :integration_deadline, :start_year=&gt; Date.today.year, :end_year =&gt;Date.today.year + 2, :order =&gt;[:month, :day, :year, :hour, :minute], :ampm =&gt; true
  </code></pre>
  
  <p>Is there any way to specifying possible values for :minute,
  for example 00,10,20,30,40,50,60 or 00,30</p>
  
  <p>currently it generates select with options</p>
  
  <pre><code>&lt;option value="00"&gt;00&lt;/option&gt;
  &lt;option value="01"&gt;01&lt;/option&gt;
  &lt;option value="02"&gt;02&lt;/option&gt;
  &lt;option value="03"&gt;03&lt;/option&gt;
  &lt;option value="04"&gt;04&lt;/option&gt;
  &lt;option value="05"&gt;05&lt;/option&gt;
  &lt;option value="06"&gt;06&lt;/option&gt;
  ...
  &lt;option value="60"&gt;60&lt;/option&gt;
  </code></pre>
  
  <p>instead, i want to get</p>
  
  <pre><code>&lt;option value="00"&gt;00&lt;/option&gt;
  &lt;option value="30"&gt;30&lt;/option&gt;
  </code></pre>
  
  <p>Thanks.</p>