delayed jobs: log to stdout.

Log to stdout because we now run workers under systemd and we want
errors to go to the journal, not to log/production.log.

config/initializers/delayed_jobs.rb

@@ -8,6 +8,7 @@ class DelayedJobTimeoutPlugin < ::Delayed::Plugin
   end
 end
 
+Delayed::Worker.logger = Logger.new(STDOUT, level: :debug)
 Delayed::Worker.default_queue_name = "default"
 Delayed::Worker.destroy_failed_jobs = false
 Delayed::Worker.plugins << DelayedJobTimeoutPlugin