ruby on rails回滚数据库创建问题

Question

I completely rolled back my migration from the beginning so I can add a few columns, now when I'm trying to create new user I get a

NoMethodError in Devise::SessionsController#create

undefined method `image_changed?' for #<User:0x007fa99ea152f8>

I'm using devise and I have carrierwave. My application worked, and I had images before, but when I rolled back and deleted the images from the upload folder, I get this undefined method.

Does anyone know where this is coming from? I'm completely clueless,

Thanks

Answer 1

I believe that inside your user model you may have carrierwave still mounted to your model.

class User < ActiveRecord::Base
  mount_uploader :image, ImageUploader  
  #mounts the uploader to the given column in this case which it is :image
end

The error undefined method image_changed?' for #` indicates that you must be missing some sort of column fro your model.

1) rails g migration AddImageToUsers image:string

2) Run rake db:migrate