resque-retry is really neat and I wanted to see how easy it would be to re-implement this generically with Rails 4.2 ActiveJob. Turns out it's pretty easy. The meat is in FollowUpEmailJob.
gem install mailcatcher
mailcatcher # Teeny SMTP server to check that the job is sending emails
# Get everything installed and serving
bundle install
rake db:create db:migrate
rackup
# Fire up Resque:
make scheduler
make workVisit http://localhost:9292/users/new and sign yourself up!
Mailcatcher shows its inbox on 1080.