migrate_to_s3.rb

# Assuming you've setup Dragonfly to use your local filesystem, here's what you would
# do to get the images over to Amazon S3

# Specify the base path to where images reside on your system
DRAGONFLY_PATH = Rails.root.join("public", "system", "dragonfly", Rails.env)

# Next you'll need to loop over each model that is using dragonfly
SlideRiff.all.each do |riff|
  slide_image_file = DRAGONFLY_PATH.join(riff.slide_image_uid)
  # check if the file exists on the local filesystem, this allows you to
  # run this if new images get added to s3 during the transition phase
  if File.exists?(slide_image_file)
    # grab the actual image file
    file = File.open(slide_image_file)
    # tell dragonfly to re-save the image which places the file onto s3
    riff.slide_image = file
    riff.save
  end
end