title: Update attributes before_save callback not saving extra attributes
body: <p>I'm using a before_save callback method to set an attribute to true if a number of other attributes are not 0. The callback is called when I update my model but the extra attribute isn't set. I think it might be because that attribute isn't passed to the update method. How do I work round that?</p>
  
  <p>Controller</p>
  
  <pre><code>@blog.update(blog_params)
  </code></pre>
  
  <p>Model</p>
  
  <pre><code>before_save do
    self.indicator = true unless attribute_1 == "0" &amp;&amp; attribute_2 == "0"
  end
  </code></pre>