Tagged queues for Resque.
In travis-ci we need workers to be able to only pull jobs that match their capabilities. E.g. a build job might be configured to require Postges or MongoDB. Then a worker should only pull that job if it has that capability.
Resque::TaggedQueues tackles this problem by defining a tagging syntax for queue names. Before pulling a job it will find all queues from Redis for which the worker has all tags that the queue requires.
Lets say the worker has 1.8.7, 1.9.2 and ree installed but it does not support jruby. It can define that by using a queue like `builds[1.8.7,1.9.2,ree]`.
Now the application queues jobs in the queues `builds[1.8.7]`, `builds[1.9.2]` and `builds[jruby]`. Then the worker will pull the jobs from `builds[1.8.7]` and `builds[1.9.2]` but ignore the one in `builds[jruby]`.
Running the tests
$ ruby -rubygems -Ilib -Itest test/tagged_queues_test.rb