title: How to make a collection_select disabled in rails 4
body: <p>I wan't to disable a collection_select and already tested the followings code:</p>
  
  <pre><code>&lt;%= f.collection_select(:categoria_id, Categoria.order(:descricao), :id, :descricao,{ class: "form-control", :disabled =&gt; "disabled" }) %&gt;
  &lt;%= f.collection_select(:categoria_id, Categoria.order(:descricao), :id, :descricao,{ class: "form-control", :disabled =&gt; true }) %&gt;
  &lt;%= f.collection_select(:categoria_id, Categoria.order(:descricao), :id, :descricao, class: "form-control", :disabled =&gt; "disabled") %&gt;
  &lt;%= f.collection_select(:categoria_id, Categoria.order(:descricao), :id, :descricao, class: "form-control", :disabled =&gt; true) %&gt;
  </code></pre>
  
  <p>None of them work, anyone know why?</p>