Support for Heroku pgbackups in Backup library

config.rb

require './lib/backup/database/heroku_pgbackups.rb'

Backup::Model.new(:heroku, 'Heroku hosted data') do
  database Backup::Database::HerokuPgbackups do |db|
    db.name = 'my-heroku-app-name'
  end

  # Followed by other databases, storage, compression, etc.
end

heroku_pgbackups.rb

require 'heroku/command'
require "pgbackups/client"

module Backup
  module Database
    class HerokuPgbackups < Base
      attr_accessor :name

      def initialize(&block)
        instance_eval(&block)
        prepare!
      end

      def perform!
        log!
        Heroku::Command.load()
        backup = Heroku::Command::Pgbackups.new(['DATABASE_URL'],{:app => name, :expire => true})
        backup.capture
        backup_client_url = ENV["PGBACKUPS_URL"] || backup.heroku.config_vars(backup.app)["PGBACKUPS_URL"]
        backup_client = PGBackups::Client.new(backup_client_url)
        backup_url = backup_client.get_latest_backup['public_url']
        File.open("#{File.join(dump_path, name)}.pgdump", 'w') do |f|
          f.binmode
          f << Net::HTTP.get(URI.parse(backup_url))
        end
      end
    end
  end
end