namespace :budgets do
  namespace :email do

    desc "Sends emails to authors of selected investments"
    task selected: :environment do
      Budget.last.email_selected
    end

    desc "Sends emails to authors of unselected investments"
    task unselected: :environment do
      Budget.last.email_unselected
    end

  end

  desc "Update investments original_heading_id with current heading_id"
  task set_original_heading_id: :environment do
    puts "Starting"
    Budget::Investment.find_each do |investment|
      unless investment.original_heading_id.present?
        investment.update_column(:original_heading_id, investment.heading_id)
      end
      print "."
    end
    puts "Finished"
  end

end

namespace :budgets do
  namespace :email do

    desc "Sends emails to authors of selected investments"
    task selected: :environment do
      Budget.last.email_selected
    end

    desc "Sends emails to authors of unselected investments"
    task unselected: :environment do
      Budget.last.email_unselected
    end

  end

  desc "Update investments original_heading_id with current heading_id"
  task set_original_heading_id: :environment do
    ApplicationLogger.new.info "Setting original_heading_id to investments"
    Budget::Investment.find_each do |investment|
      unless investment.original_heading_id.present?
        investment.update_column(:original_heading_id, investment.heading_id)
      end
      print "."
    end
  end

end

Use application logger in set_original_heading_id
Use application logger in set_original_heading_id

The pull request adding the original heading was done before we started
using `ApplicationLogger` in rake tasks.
