Jcrop error: undefined method 'sub'

Question

Rails 4.0.10: I've been following this Jcrop tutorial: (http://railscasts.com/episodes/182-cropping-images), and I've gotten as far as submitting the cropped image. But when I press the submit button, I get this error:

NoMethodError in ThingsController#update
undefined method `sub' for ["-auto-orient", "-resize", "\"500x500\""]:Array

I saw another question with the same error, which was fixed by changing super.sub(/ -crop... in lib/paperclip_processor/cropper to "super.first.sub(/ -c..., but this just returned the same exact error in my case. Has anyone else run into this issue with Jcrop?

---

lib/paperclip_processors/cropper (I put asterisks around the line highlighted on the error page)

module Paperclip
  class Cropper < Thumbnail
    def transformation_command
      if crop_command
        ***crop_command + super.sub(/ -crop \S+/, '')***
      else
        super
      end
    end

    def crop_command
      target = @attachment.instance
      if target.cropping?
        " -crop '#{target.crop_w}x#{target.crop_h}+#{target.crop_x}+#{target.crop_y}' "
      end
    end
  end
end

---

views/things/crop.html.erb

<% content_for(:head) do %>
<%= stylesheet_link_tag "jquery.Jcrop" %>
<%= javascript_include_tag "jquery.Jcrop.min" %>
<script type="text/javascript" charset="utf-8">
ready = $(function() {
  $("#cropbox").Jcrop({
    onChange: update_crop,
    onSelect: update_crop,
    setSelect: [0, 0, 500, 500],
    aspectRatio: 1
  });
});

function update_crop(coords) {
  $("#crop_x").val(coords.x);
  $("#crop_y").val(coords.y);
  $("#crop_w").val(coords.w);
  $("#crop_h").val(coords.h);
}

$(document).ready(ready);
$(document).on('page:load', ready);

</script>
<% end %>

<%= image_tag @thing.avatar.url(:large), :id => "cropbox" %>

<%= form_for @thing do |f| %>
  <% for attribute in [:crop_x, :crop_y, :crop_w, :crop_h] %>
    <%= f.text_field attribute, :id => attribute %>
  <% end %>
  <p><%= f.submit "Crop" %></p>
<% end %>

---

models/thing.rb

class Thing < ActiveRecord::Base
  # ...
  has_attached_file :avatar, :styles => { :large => "500x500", :medium => "300x300>", :thumb => "50x50!" }, :processors => [:cropper]
  validates_attachment_content_type :avatar, :content_type => /\Aimage\/.*\Z/
  attr_accessor :crop_x, :crop_y, :crop_w, :crop_h
  after_update :reprocess_avatar, :if => :cropping?  

  def cropping?
    !crop_x.blank? && !crop_y.blank? && !crop_w.blank? && !crop_h.blank?
  end

  private

  def reprocess_avatar
    avatar.reprocess!
  end

end