Change Public Folder Location in Rails

How do you change the public folder location in a rails (3.2.8) application?

I found this page: http://ift.tt/1J6ek2w which says to change paths.public in the config/application.rb file but when I do i get: undefined method `public=' for # (NoMethodError)

The code I used was: paths.public = '/home/user/public'

Thanks!