carrierwaveuploader/carrierwave — pull request #1402 by rocLv (2014-06-07 06:08:12+00:00)
Title: Add content about how to modify controller within Rails 3 and Rails 4

This tutorial is missing how to modify controller code.
There is an tutorial about how to use this gem, but it based on Rails 3.
The attr_accessible method has removed from Rails 4, so when you use Rails 4, you should edit strong params.

Change this code just for beginners like me.