A default unicorn config for a Rack app (not Rails) on Heroku

unicorn.rb

worker_processes 3
timeout 10
preload_app true

before_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
    Process.kill 'QUIT', Process.pid
  end

  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.connection.disconnect!
end 

after_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to send QUIT'
  end

  defined?(ActiveRecord::Base) and
    config = ActiveRecord::Base.configurations[ENV['RACK_ENV'].to_sym]
    ActiveRecord::Base.establish_connection(config)
end