title: How do I duplicate a file stored in ActiveStorage in Rails 5.2
body: <p>I have a model that is using ActiveStorage:</p>
  
  <pre><code>class Package &lt; ApplicationRecord
    has_one_attached :poster_image
  end
  </code></pre>
  
  <p>How do I create a copy of a Package object that contains a duplicate of the initial poster_image file. Something along the lines of:</p>
  
  <pre><code>original = Package.first
  copy = original.dup
  copy.poster_image.attach = original.poster_image.copy_of_file
  </code></pre>