Generating the User Model : undefined method `first_name'

So (I think) I've been following the videos word for word, yet I seem to be running into an error just after adding in the modifications to the sign up page in new.html.erb where you need to add text fields for First Name, Last Name and Profile Name.

After migrating, I seem to be getting this error :

" NoMethodError in Devise/registrations#new

Showing C:/Users/Andrew/Projects/treebook/app/views/devise/registrations/new.html.erb where line #6 raised:

undefined method `first_name' for #<User:0x3cbc8b0> "

Which of course is now driving me crazy because as I say, I think I've followed everything correctly. I'm aware that there is actually supposed to be a error showing by the end of this section, but... I'm not there yet, this is a different error showing just before I get to the 'planned' one. I know its impractical to show my entire code for every single bit so I can identify where I've obviously made a mistake, but, could anyone please offer advice on where I should be looking in terms of common mistakes?

Thanks.

EDIT

Thanks anyways but I have since solved my problem, I dont know why but for some reason my migrations were not working, so, to fix it, I used db:rollback and the db:migrate again and this fixed it.