title: Rails add one to increment SQL value
body: <p>I am trying to add one to the already incremented field in the DB, but I am getting the following error: <code>NoMethodError (undefined method</code>+' for false:FalseClass):`</p>
  
  <p>Code:</p>
  
  <pre><code>med = Media.find(params[:media_id])
  med.update_attributes({:screener_viewed =&gt; med.screener_viewed + 1})
  </code></pre>
  
  <p>I am just wanting to add <code>1</code> to the current value of screener_viewed, but can't get it to work.</p>
  
  <p>Working Code:</p>
  
  <pre><code>Media.increment_counter(:screener_viewed, params[:media_id])
  </code></pre>