10 things I usually do after creating rails app on heroku

• add rediscloud add-on (free 20MB plan)
• add sentry exception notifier with hipchat plugin notification
• setup web dyno to start background sidekiq process
• change Procfile to use unicorn server for huge performance improvement
• add 'use Rack::Deflater' to config.ru to html compress pages with gzip
• setup deploy hooks to notify hipchat about deployments
• configure newrelic for performance monitoring
• mount Sidekiq::Web to monitor background jobs
• setup Zerigo DNS for custom domain handling
• add figaro gem to handle configuration from heroku env

order is random...