title: Validates acceptance always failing
body: <p>I can't see what I'm missing, but something is obviously not right.</p>
  
  <p>In model:</p>
  
  <pre><code>validates :terms, :acceptance =&gt; true, :on =&gt; :update
  </code></pre>
  
  <p>Trying a few options:</p>
  
  <pre><code>&gt;&gt; a = Factory(:blog_agreement)
  =&gt; #&lt;BlogAgreement id: 54, terms: false, created_at: "2011-01-20 11:33:03", updated_at: "2011-01-20 11:33:03", accept_code: "fa27698206bb15a6fba41857f12841c363c0e291", user_id: 874&gt;
  
  &gt;&gt; a.terms
  =&gt; false
  
  &gt;&gt; a.terms = true
  =&gt; true
  &gt;&gt; a.save
  =&gt; false
  
  &gt;&gt; a.terms = "1"
  =&gt; "1"
  &gt;&gt; a.save
  =&gt; false
  
  &gt;&gt; a.terms = 1
  =&gt; 1
  &gt;&gt; a.save
  =&gt; false
  &gt;&gt; a.errors.full_messages
  =&gt; ["Terms must be accepted"]
  </code></pre>