Heroku - ActionView::Template::Error (PG::Error: ERROR: column category_products.desc does not exist

问题

I am using RailsAdmin and this is the error I get when I click on my model CategoryProduct within RailsAdmin.

This is what the error looks like:

Started GET "/admin/category_product" for 67.230.41.62 at 2012-12-21 23:20:07 +0000
2012-12-21T23:20:07+00:00 app[web.1]: 
2012-12-21T23:20:07+00:00 app[web.1]: ActionView::Template::Error (PG::Error: ERROR:  column category_products.desc does not exist
2012-12-21T23:20:07+00:00 app[web.1]: LINE 1: ...ry_products".* FROM "category_products"  ORDER BY category_p...
2012-12-21T23:20:07+00:00 app[web.1]:                                                              ^
2012-12-21T23:20:07+00:00 app[web.1]: : SELECT  "category_products".* FROM "category_products"  ORDER BY category_products. desc LIMIT 20 OFFSET 0):
2012-12-21T23:20:07+00:00 app[web.1]:     120:       %tbody
2012-12-21T23:20:07+00:00 app[web.1]:     121:         - @objects.each do |object|
2012-12-21T23:20:07+00:00 app[web.1]:     122:           %tr
2012-12-21T23:20:07+00:00 app[web.1]:     123:             %td
2012-12-21T23:20:07+00:00 app[web.1]:     124:               = check_box_tag "bulk_ids[]", object.id, false
2012-12-21T23:20:07+00:00 app[web.1]:     125:             - if @other_left_link ||= other_left && index_path(params.except('set').merge(params[:set].to_i != 1 ? {:set => (params[:set].to_i - 1)} : {}))
2012-12-21T23:20:07+00:00 app[web.1]:     126:               %td.other.left= link_to "...", @other_left_link, :class => 'pjax'^

These are my category, product & category_product models:

Category.rb

# == Schema Information
#
# Table name: categories
#
#  id         :integer          not null, primary key
#  name       :string(255)
#  created_at :datetime         not null
#  updated_at :datetime         not null
#

class Category < ActiveRecord::Base
  attr_accessible :name
    has_many :category_products do
         def with_products
           includes(:product)
         end
       end

  has_many :products, :through => :category_products

  def top_products(number)
    category_products.with_products.order("purchases_count DESC").limit(number).map {|c| c.product} # product included
  end

end

Product.rb

# == Schema Information
#
# Table name: products
#
#  id          :integer          not null, primary key
#  name        :string(255)
#  description :string(255)
#  price       :float
#  vendor_id   :integer
#  created_at  :datetime         not null
#  updated_at  :datetime         not null
#  image       :string(255)
#

class Product < ActiveRecord::Base
  attr_accessible :name, :description, :price, :vendor_id, :image, :category_ids
    mount_uploader :image, ImageUploader

    belongs_to :vendor
    has_many :category_products do
           def with_categories
             includes(:category)
           end
    end

    has_many :categories, :through => :category_products

  def top_categories(number)
    category_products.with_categories.order("purchases_count DESC").limit(number).map {|c| c.category} # category included
  end

end

Category_Product

# == Schema Information
#
# Table name: category_products
#
#  id              :integer          not null, primary key
#  product_id      :integer
#  category_id     :integer
#  purchases_count :integer          default(0)
#  created_at      :datetime         not null
#  updated_at      :datetime         not null
#

class CategoryProduct < ActiveRecord::Base
  attr_accessible :product_id, :category_id, :purchases_count

    belongs_to :product
  belongs_to :category

  validates_uniqueness_of :product_id, :scope => :category_id
end

Any ideas what may be causing this?

Thanks.