Basic implementation.
Revised implementation of Foxx queues.
Exposed Foxx.queues._manager.run.
Fixed Foxx.queues.
Implemented worker/manager internals.
Linting. :boom:
Removed unused variable.
More consistent naming.
Cache queue objects.
Allow creating queues with default number of workers, don't update queue if maxWorkers is not set.
Return number of pending jobs in queue on push.
Add chapter on Foxx Job Queues.
Added intro.
Renamed queues.destroy => queues.delete.
Extracted worker, manager modules from queue. Implemented backOff, delayUntil, success/failure callbacks, push(maxFailures).
start the queue manager once during boot
Fixed undefined CLUSTER_COORDINATOR.
fixed tests, log can contain more entries
Added support for job type schemas.
Merge pull request #962 from triAGENS/foxx-queue

[WIP] Foxx queues