sidekiq.rb

redis_config =  { :namespace => 'sidekiq', :url => YAML.load_file("#{Rails.root}/config/redis.yml")[Rails.env] }
Sidekiq.configure_server do |config|
  config.redis = redis_config
end
Sidekiq.configure_client do |config|
  config.redis = redis_config
end

Note that both comments are now wrong.

poll interval can be configured directly:

Sidekiq.configure_server do |config|
  config.poll_interval = 1
end

and Passenger's starting_worker_process or Unicorn's after_fork is no longer necessary since Sidekiq 2.9.0.