Re: #132 and #137, the zero-downtime approach starts a new pool while the old pool is still running. Although this is usually fine, it can lead to issues in memory-constrained environments. Our default config loader should take workers from other pools (or orphaned workers with no pool) into account.

See https://github.com/backupify/resque-pool/compare/nevans:master and the discussion on #132. I prefer reading Resque.redis.smembers("workers") to looking at ps, but ps might be more fool-proof.