title: rails, simple_form, how to set selected index of a collection when page loaded?
body: <p>I am using simple_form gem, I have a countries collection, it work fine when I select the country, and updated record will have the country id stored, but, when I try to edit the record, the chosen country is not selected by default at edit form.</p>
  
  <p>Here is the code at edit form:</p>
  
  <pre><code>= f.input :country_id, :collection =&gt; all_countries
  </code></pre>
  
  <p>Shouldn't simple_form view the selected country from the db ?</p>