app/uploaders/logo_image_uploader.rb
class LogoImageUploader < CarrierWave::Uploader::Base
include CarrierWave::MiniMagick
# https://github.com/DarthSim/carrierwave-bombshelter
storage :fog
def store_dir
"images/#{model.class.to_s.pluralize.underscore}/#{mounted_as}/#{model.id}"
end
def extension_white_list
%w(jpg jpeg gif png)
end
end