Port activerecord 6 support from QC::Queue
Port activerecord 6 support from QC::Queue

original commit (https://github.com/QueueClassic/queue_classic/commit/6ab7dfa4ce658f3b84ef59e7fbe39d6e5586d319) resolves `no implicit conversion of Time into String`.

rainforestapp/queue_classic_plus,rainforestapp/queue_classic_plus