old-ribica/back-office/app/models/category.rb

class Category < ActiveRecord::Base
  has_many  :sub_categories
  has_many :filter_criterias, as: :owner
  belongs_to :section

  rails_admin do 
    object_label_method do
      :custom_cat_name
    end
  end

  def custom_cat_name
    return self.name if not self.section

    section = self.section.name
    "#{section} -> #{self.name}"
  end

end