This is a simple rake task to deploy an app to heroku.

Rakefile.rb

# Deploy and rollback on Heroku in qa and production
# sources: https://gist.github.com/njvitto/362873
# https://gist.github.com/djburdick/4410411
task :deploy_qa_light => ['deploy:set_qa_app', 'deploy:push', 'deploy:tag']
task :deploy_production_light => ['deploy:set_production_app', 'deploy:push', 'deploy:tag']

namespace :deploy do
  PRODUCTION_APP = 'my-heroku-prod-app'
  QA_APP = 'my-heroku-qa-app'

  task :qa_migrations => [:set_qa_app, :push, :collectstatic, :off, :migrate, :restart, :on, :tag]
  task :qa_rollback => [:set_qa_app, :off, :rollback, :collectstatic, :restart, :on]

  task :production_migrations => [:set_production_app, :push, :collectstatic, :off, :backup_prod_db, :migrate, :restart, :on, :tag]
  task :production_rollback => [:set_production_app, :off, :rollback, :collectstatic, :restart, :on]

  task :refresh_qa_db => [:set_qa_app, :off, :transfer_prod_db_to_qa, :on]

  task :backup_prod_db => :set_production_app do
    puts 'Backing up production database ...'
    system("heroku pgbackups:capture --app #{PRODUCTION_APP} --expire")
  end

  task :set_qa_app do
    APP = QA_APP
    puts "=== APP #{APP} ==="
  end

  task :set_production_app do
    APP = PRODUCTION_APP
    puts "=== APP #{APP} ==="
  end

  task :push do
    current_branch = `git rev-parse --abbrev-ref HEAD`.chomp
    current_branch += ":master" if current_branch != "master"
    puts "Deploying #{current_branch} to #{APP} ..."
    system("git push #{'-f' if APP == QA_APP} [email protected]:#{APP}.git #{current_branch}")
  end

  task :restart do
    puts 'Restarting app servers ...'
    puts `heroku restart --app #{APP}`
  end

  task :tag do
    release_name = "#{APP}_release-#{Time.now.utc.strftime("%Y%m%d%H%M%S")}"
    puts "Tagging release as '#{release_name}'"
    puts `git tag -a #{release_name} -m 'Tagged release'`
    puts `git push --tags [email protected]:#{APP}.git`
  end

  task :migrate do
    puts 'Running database migrations ...'
    puts `heroku run python manage.py migrate --app #{APP}`
  end

  task :collectstatic do
    puts 'Collecting static assets ...'
    puts `heroku run python manage.py collectstatic --noinput   --app #{APP}`
  end

  task :off do
    puts 'Taking the app offline ...'
    puts `heroku maintenance:on --app #{APP}`
    puts `heroku ps:scale web=0 --app #{APP}`
    puts `heroku ps:scale celeryd=0 --app #{APP}`
  end

  task :on do
    puts 'Bringing the app online ...'
    puts `heroku ps:scale web=1 --app #{APP}`
    puts `heroku ps:scale celeryd=1 --app #{APP}`
    puts `heroku maintenance:off --app #{APP}`
  end

  task :rollback do
    puts 'Rolling back to last version ...'
    system("heroku rollback --app #{APP}")
  end

  task :transfer_prod_db_to_qa do
    puts 'Transfering prod DB to QA db ...'
    system("heroku pg:reset DATABASE --app #{QA_APP} --confirm #{QA_APP}")
    #reset is needed to completely drop db
    #restoring only overwrites tables within the restore file - newer tables are not untouched
    #which causes migration issues
    system("heroku pgbackups:restore DATABASE --app #{QA_APP} --confirm #{QA_APP} `heroku pgbackups:url --app #{PRODUCTION_APP}`")
  end
end