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GitHub User: otagi
You are correct, Heroku requires a separate worker dyno to launch background jobs.
You can use the Workless gem, which creates and kills a worker when DelayedJob is called. Heroku will only bill you the uptime ($0.05/h), not the full $35/m.
Great screencast as always.
Confirmation boxes are still useful, though. Undoing changes on a model with a Paperclip attachment is less trivial.