make Resque scheduler write to PIDFILE

resque.rake

require 'resque/tasks'
require 'resque_scheduler/tasks'
task "resque:setup" => :environment

desc "Start Resque Scheduler"
task 'resque:scheduler' => :scheduler_setup do
  require 'resque'
  require 'resque_scheduler'

  File.open(ENV['PIDFILE'], 'w') { |f| f << Process.pid.to_s } if ENV['PIDFILE']

  Resque::Scheduler.dynamic = true if ENV['DYNAMIC_SCHEDULE']
  Resque::Scheduler.verbose = true if ENV['VERBOSE']
  Resque::Scheduler.run
end

task :scheduler_setup do
  if ENV['INITIALIZER_PATH']
    load ENV['INITIALIZER_PATH'].to_s.strip
  else
    Rake::Task['resque:setup'].invoke
  end
end