Delayed_paperclip setup using Sidekiq

sidekiq_delayed_paperclip.rb

###gemfile
gem 'paperclip' ## 3.5.1, also 3.4.2 previously
gem 'delayed_paperclip'
gem 'sidekiq', '2.6.4'

### image.rb

attr_accessible :photo_processing
has_attached_file :photo, 
                    styles: {
                      default: '480x360#',
                      square: '200x200#'
                          
                    }, 
                    convert_options: { default: '-interlace Plane -quality 85', square: '-interlace Plane -quality 85' },
                    storage: :s3,
                    bucket: 'workhands_images',
                    default_url: "/assets/license_avatar.jpg"
                    
process_in_background :photo, processing_image_url: '/assets/processing-image.png'

### sidekiq.yml
:concurrency: 7
:queues:
  - [high, 7]
  - [default, 5]
  - [paperclip, 5]