I suppose one could go totally overboard and have an environment prefix argument which defaulted to ``RQ_`` or ``REDIS_`` :boom: 

That said, I do think ``REDIS_HOST`` is good enough; certainly, ``RQ_HOST`` means nothing so it would have to be ``RQ_REDIS_HOST``.

But consider this: if another library did indeed look in ``REDIS_HOST``, what are the odds that these two hosts would not be the same? Who would use ``rq-scheduler`` with two different redis servers?