title: problem with passing booleans to update_attributes
body: <p>I've got the following Model:</p>
  
  <pre><code>class GuestCatering &lt; ActiveRecord::Base
  
    # Validation
    validates :name, :presence =&gt; true
    validates :order_number, :presence =&gt; true
    validates :orderable, :presence =&gt; true
  
  end
  </code></pre>
  
  <p>But when I'll try to update an existing GuestCatering with the following code:</p>
  
  <pre><code>guest_catering.update_attributes(:orderable =&gt; false)
  </code></pre>
  
  <p>The guest catering variable is a valid GuestCatering object.
  The guest_catering object has errors after the update, like that:</p>
  
  <pre><code>&lt;{[:orderable, ["can't be blank"]]=&gt;nil}&gt;
  </code></pre>
  
  <p>But when i pass a <code>orderable =&gt; true</code>, everything is fine and no errors.</p>
  
  <p>What's wrong here, why can't i set orderable to false?</p>