Rails 4 and Devise named routes fail with undefined local variable or method after upgrade from rails 3

Rails 4 and Devise named routes fail with undefined local variable or
method after upgrade from rails 3

After upgrading to rails 4, named routes under devise scope block no
longer work. They also do not appear with rake routes.
I tried match/get it just always fails inside the devise block. I thought
I had to define those devise specific routes inside the devise block?
Feels like very stupid mistake, but cannot pinpoint my error. Who can help
me pinpoint the mistake? thanks!
Routes.rb
devise_for :users, :controllers => {:sessions => "users/sessions",
:registrations =>
"users/registrations",
:confirmations =>
"users/confirmations",
:passwords => "users/passwords",
:unlocks => "users/unlocks"} do
get "/signup" => "users/registrations#new" , :via
=> [ :get, :post ]
end
In view im using:
= link_to t('home.beta.got_invitation_code'), signup_path
The error:
undefined local variable or method `signup_path' for...