Resque workers are terminated by Heroku within 10 seconds

heroku_log.txt

07:36+00:00 app[worker.1]: *** got: (Job{jobs} | Job | [1, 100])
07:37+00:00 app[worker.1]: Processed 1
07:38+00:00 app[worker.1]: Processed 2
07:39+00:00 app[worker.1]: Processed 3
07:40+00:00 app[worker.1]: Processed 4
07:41+00:00 app[worker.1]: Processed 5
07:42+00:00 app[worker.1]: Processed 6
07:43+00:00 app[worker.1]: Processed 7
07:44+00:00 app[worker.1]: Processed 8
07:45+00:00 app[worker.1]: Processed 9
07:46+00:00 heroku[worker.1]: State changed from up to stopping
07:46+00:00 heroku[api]: Scale to web=1, worker=0 by mike@quickleft.com
07:46+00:00 app[worker.1]: Processed 10
07:47+00:00 app[worker.1]: Processed 11
07:48+00:00 app[worker.1]: Processed 12
07:48+00:00 heroku[worker.1]: Stopping all processes with SIGTERM
07:49+00:00 app[worker.1]: *** Exiting...
07:49+00:00 app[worker.1]: Processed 13
07:50+00:00 app[worker.1]: Processed 14
07:51+00:00 app[worker.1]: Processed 15
07:52+00:00 app[worker.1]: Processed 16
07:53+00:00 app[worker.1]: Processed 17
07:54+00:00 app[worker.1]: Processed 18
07:55+00:00 app[worker.1]: Processed 19
07:56+00:00 app[worker.1]: Processed 20
07:57+00:00 app[worker.1]: Processed 21
07:58+00:00 app[worker.1]: Processed 22
07:59+00:00 heroku[worker.1]: Error R12 (Exit timeout) -> At least one process failed to exit within 10 seconds of SIGTERM
07:59+00:00 heroku[worker.1]: Stopping remaining processes with SIGKILL
07:59+00:00 app[worker.1]: Processed 23
08:00+00:00 heroku[worker.1]: Process exited with status 137

job.rb

class Job
  @queue  = :jobs

  def self.perform from, through
    (from..through).each do |item|
      sleep 1
      puts "Processed #{item}"
    end
  end
end