add worker's queues to $0

[rab]

As my use-case is to take advantage of having multiple queues and dedicating workers with overlapping coverage of them (to ensure that jobs in the high_priority queue have more workers servicing them, but that low_priority jobs aren't completely starved out), I'd really like to know which workers are handling which queues. This change makes that easy to see from just the ps output (or from pgrep -fal delayed_job)

[coveralls]

Coverage decreased (-0.2%) to 90.95% when pulling b46a145 on scrumalliance:master into 71f1d5f on collectiveidea:master.

[coveralls]

Coverage increased (+0.008%) to 91.129% when pulling a02cf9a on scrumalliance:master into 71f1d5f on collectiveidea:master.

[coveralls]

Coverage increased (+0.008%) to 91.208% when pulling d4ed3e1 on scrumalliance:master into 1e67917 on collectiveidea:master.