Paperclip & Amazon S3

development.rb

# environments/{development.rb || test.rb}
# Left blank to skip s3 in development.
PAPERCLIP_STORAGE_OPTIONS = {}

picture.rb

# models/picture.rb
has_attached_file :attachment, { :styles => { :thumbnail => "x80>" },
    :url => "/system/attachments/:hash.:extension", :hash_secret => "UMdHdTJhPZqoD1ffOWv" }.merge(PAPERCLIP_STORAGE_OPTIONS)

production.rb

# environments/production.rb
PAPERCLIP_STORAGE_OPTIONS = { :storage => :s3,
                                :s3_credentials => "#{Rails.root}/config/s3.yml",
                                :path => ":attachment/:id/:style/:basename.:extension"
                             }

s3.yml

# /config/s3.yml
development:
  access_key_id: access_key_id_goes_here
  secret_access_key: secret/access_key_goes_here
  bucket: dev_bucket_name_goes_here
production:
  access_key_id: access_key_id_goes_here
  secret_access_key: secret/access_key_goes_here
  bucket: bucket_name_goes_here