Created by: alanclarke
This pr makes bull compatible with the ioredis keyPrefix option, which has a number of benefits:
- queues can be namespaced transparently to prevent conflicts
- people expecting the keyPrefix option to work for free will have a better time
- easier redis key grepping
When lua scripts are constructed with strings, keys must be manually prefixed. ioredis commands are transparently prefixed... even the key args to .evalsha