Often I want to evaluate what changed on an object after it has saved and has been transactionally committed. One use case is enqueuenig a background job when a specific attribute changed. Typically you should wait until after_commit to enqueue the job. This ensures that your workers will have access to the updates that were being made inside the transaction. This is a problem because ActiveRecord forgets the changes after_save. This gem keeps those changes around for later inspection and evaluation.
Gemfile gem 'nostalgia', '~> 0.0.1'
install gem install nostalgia