Restart Task and Debug with ruby-debug

development.rb

# ... bottom of your development.rb

if File.exists?(File.join(RAILS_ROOT,'tmp', 'debug.txt'))
  require 'ruby-debug'
  Debugger.wait_connection = true
  Debugger.start_remote
  File.delete(File.join(RAILS_ROOT,'tmp', 'debug.txt'))
end

restart.rake

# add this rake file to your lib/tasks folder
task :restart do
  system("touch tmp/restart.txt")
  system("touch tmp/debug.txt") if ENV["DEBUG"] == 'true'
end