Some simple Heroku deploy rake tasks.

heroku.rake

namespace :heroku do
  namespace :deploy do
    task :tag do
      rev = `git rev-parse HEAD`.strip
      if `git describe --contains #{rev} 2>&1`.include?('cannot describe')
        version = Time.new.strftime("%Y%m%d%H%M%S")
        sh "git tag -a heroku-#{version} -m 'Deploy version to Heroku: #{version}'"
        sh "git push origin master"
        sh "git push origin master --tags"
      else
        puts "[!] The current revision is already tagged, skipping tag creation."
      end
    end

    task :no_migrations => 'heroku:deploy:tag' do
      sh "git push heroku master"
      sh "git push heroku master --tags"
    end

    desc 'Deploys *and* runs migrations (this will turn maintenance mode on)'
    task :migrate => 'heroku:deploy:tag' do
      Bundler.with_clean_env do
        sh "heroku maintenance:on"
        sh "git push heroku master"
        sh "git push heroku master --tags"
        sh "heroku rake db:migrate"
        sh "heroku restart"
        sh "heroku maintenance:off"
      end
    end
  end

  desc 'Deploys *without* running migrations'
  task :deploy => 'heroku:deploy:no_migrations'
end