set Solid-Queue's config via environment variables

[gsilvan]

I'm running fizzy on my VPS via Docker and noticing pretty high cpu usage from solid-queue-worker in idle. I've kinda like mitigated it by increasing the polling_interval in config/queue.yml.

My edited queue.yml looks like this now:

default: &default
  dispatchers:
    - polling_interval: 2
      batch_size: 500
  workers:
    - queues: [ "default", "solid_queue_recurring", "backend", "webhooks", "*" ]
      threads: 2
      processes: <%= Integer(ENV.fetch("JOB_CONCURRENCY") { Concurrent.physical_processor_count }) %>
      polling_interval: 2

development: *default
test: *default
beta: *default
staging: *default
production: *default

It would be comfortable for me to set these settings via environment variables, so i could keep the source-code untouched.