I needed to assign priority dynamically (at the time the job is queued up) with Resque.

application_job.rb

class ApplicationJob
  def self.set_priority(queue, priority)
    if [:high, :medium, :low].include?(priority)
      self.instance_eval do
        @queue = "#{queue}_#{priority}".to_sym
      end
    end
  end
end

gistfile2.ru

OurJob.set_priority(:our_queue, :high)
Resque.enqueue(OurJob, "Hello world!")

gistfile3.sh

export QUEUE=our_queue_high,our_queue_medium,our_queue_low

our_job.rb

# Notice I've left the @queue variable unassigned.

class OurJob < ApplicationJob
  def self.perform(str)
    puts str
  end
end