generates a CSV file where the first column is category titles in "crumbs" format for BR, second column is category IDs in "crumb_ids" format for BR.

generate_crumbs_csv_service.rb

class GenerateCrumbsCsvService
  def self.perform
    data = []
    Category.where(listed: true, depth: 2).each do |category|
      crumbs_id = [category.parent.parent._id.to_s, category.parent._id.to_s, category._id.to_s].join("|")
      crumbs = [category.parent.parent.title, category.parent.title, category.title].join("|") 
      data.push([crumbs, crumbs_id])
    end

    CSV.open("/tmp/crumbs.csv", "w") do |csv|
      data.each do |data_row|
        csv << data_row
      end
    end    
  end
end