class User < ActiveRecord::Base
  # Not needed! This is done using a hook on ActiveRecord::Base.
  # include Resque::Plugins::Async::Method
  def preprocess_avatar_for_a_long_time
    # do stuff
  end
  async_method :preprocess_avatar_for_a_long_time
  def send_a_very_long_email
    # do stuff
  end
  async_method :send_a_very_long_email, queue: 'emails'
end
u = User.find(1)
u.preprocess_avatar_for_a_long_time # => queued in 'users' queue
u.send_a_very_long_email # => queued in 'emails' queue
u.sync_send_a_very_long_email # => happens right away!

module MyExtension
  extend ActiveSupport::Concern
  include Resque::Plugins::Async::Method
  included do
    async_method :generate_matrix, queue: 'matrices'
  end
  def generate_matrix
    # do stuff
  end
end