use sidekiq for background job
use sidekiq in unicorn, under 1 heroku web dyno
Add sentry to monitor error
Add sentry to monitor error
Use the Paratrooper gem to automate the deploy pipeline
Add recipient_interceptor, only send email to specify recipients in staging server
config redis cloud for heroku
use mailcatcher in vm
add sidekiq monitoring, add admin to user
separate staging and production.rb