Rendering rails named route - ruby-on-rails

Question

How do I render a rails named route properly from controller?
routes.rb:
get "logout" => "sessions#destroy", :as => "logout"
get "login" => "sessions#new", :as => "login"
get "signup" => "users#new", :as => "signup"
root :to => "home#index"
resources :users
resources :sessions
resources :likes
user_controller.rb:
def new
#user = User.new
end
def create
#user = User.new params[:user]
if #user.save
login(params[:user][:email], params[:user][:password])
redirect_to root_url, :notice => "Welcome! You have signed up successfully."
else
render :new
end
end
Problem is: the signup page is on /signup and when the data in #user is not filled out properly and render :new is called, instead of going to the url /signup it goes to /users. I would use redirect_to but id prefer not to because I want the errors saved off on the page to tell the users which data was not provided.
Update after added match "signup" => "users#create", :via => "post"
root / {:controller=>"home", :action=>"index"}
users GET /users(.:format) {:action=>"index", :controller=>"users"}
POST /users(.:format) {:action=>"create", :controller=>"users"}
edit_user GET /users/:id/edit(.:format) {:action=>"edit", :controller=>"users"}
user GET /users/:id(.:format) {:action=>"show", :controller=>"users"}
PUT /users/:id(.:format) {:action=>"update", :controller=>"users"}
DELETE /users/:id(.:format) {:action=>"destroy", :controller=>"users"}
signup GET /signup(.:format) {:action=>"new", :controller=>"users"}
POST /signup(.:format) {:action=>"create", :controller=>"users"}
Thanks

Answer 1

Add this route also:
match "signup" => "users#create", :via => "post"

Answer 2

In routes.rb You can add
get "signup", to: "users#new"
post "signup", to: "users#create"
put "signup", to: "users#update"
And in Registration form - Check signup_path
form_for(resource, as: resource_name, url: signup_path, html: {method: 'post'})
For Other Readers who has used devise_for :users, can defined routes as:
devise_scope :user do
get "signup", to: "devise/registrations#new"
post "signup", to: "devise/registrations#create"
put "signup", to: "devise/registrations#update"
end
And Registration form as above.
By adding this routes, you can use your named routes like (register, signup) even after user fills register form with some error.