title: Money-Rails - Simple Form Input
body: <p>I'm using the money-rails gem for one of my Models to store the cost of manufacture.</p>
  
  <p>In my model I have - </p>
  
  <pre><code>monetize :cost_of_manufacturing_cents
  </code></pre>
  
  <p>And in the _form.html view I have for simple_form : </p>
  
  <pre><code>f.input :cost_of_manufacturing
  </code></pre>
  
  <p>However, when I run the item/new route, I get the following error</p>
  
  <pre><code>undefined method `cost_of_manufacturing' for #&lt;Item:0x007fe34a5feaf8&gt;
  </code></pre>
  
  <p>How can I resolve this issue?</p>