Run "rails g uploader image"
Run "rails g scaffold item name:string price:integer image:string"
Run "rake db:migrate"
Use "image" column for image file
Ignore storage directory for uploaded files
Fix views
Include "CarrierWave::RMagick"

ref.
  https://github.com/carrierwaveuploader/carrierwave#adding-versions
  https://github.com/carrierwaveuploader/carrierwave#using-rmagic
Add "normal" version to "image"
Fix views (adding normal version)