Devise disable signup

routes

devise_for :users, :skip => [:registrations] 
as :user do
  get 'users/edit' => 'devise/registrations#edit', :as => 'edit_user_registration'
  put 'users' => 'devise/registrations#update', :as => 'user_registration'
end

# And then modify the app/views/devise/shared/_links.erb

I agree with @CoryFoy, removing :registerable from the model makes the sign up link not to be rendered in the form and the route not being generated.