I want user to work with only one order connected to user's session. So I set singular resource for order routes.rb: resource :order views/orders/new.html.erb: <%= form_for @order do |f| %> ... <% end %> But when I open the new order page I get an error: undefined method `orders_path` I know, that I can set :url => order_path in form_for, but what is the true way of resolving this collision?