[Rails]concernをrake taskの中で使う

結論：これをrake taskに入れればよい

require 'active_support/concern'

実例

concernの所在

app/controllers/concerns/test_concern.rb

module TestConcern
  extend ActiveSupport::Concern
    def test_method(test)
      略
    end
  end
end

rake task

lib/tasks/test_task.rake

namespace :task do
  task test_rake_task: :environment do
    require 'active_support/concern'
    include TestConcern
      略
    end
  end
end