discourse/config/initializers/001-redis.rb

if Rails.env.development? && ENV['DISCOURSE_FLUSH_REDIS']
  puts "Flushing redis (development mode)"
  $redis.flushall
end

if defined?(PhusionPassenger)
  PhusionPassenger.on_event(:starting_worker_process) do |forked|
    if forked
      Discourse.after_fork
    else
      # We're in conservative spawning mode. We don't need to do anything.
    end
  end
end