title: Question about update_all in Ruby
body: <p>I created an array using this statement..</p>
  
  <pre><code>users_who_promoted = @organization.card_signups.select {|c| c.credit_status == true }
  </code></pre>
  
  <p>but when I do this :</p>
  
  <pre><code>users_who_promoted.update_all("credit_status = false")
  </code></pre>
  
  <p>I get a big error :</p>
  
  <pre><code>NoMethodError: undefined method `update_all' for #&lt;Array:0x32377bc&gt;
  from (irb):25
  </code></pre>
  
  <p>Why is this?</p>