module ActiveRecord::Transactions::ClassMethods

after_commit :do_bar_baz, on: [:update, :destroy]
after_commit :do_foo_bar, on: [:create, :update]

after_commit :do_baz, on: :destroy
after_commit :do_bar, on: :update
after_commit :do_foo, on: :create

the +:on+ option:
You can specify that the callback should only be fired by a certain action with

This callback is called after a record has been created, updated, or destroyed.

def after_commit(*args, &block)
  set_options_for_callbacks!(args)
  set_callback(:commit, :after, *args, &block)
end