如何删除Clearance生成的默认路由？

match \'login\'  => \'clearance/sessions#new\', :as => \'sign_in\'
match \'logout\' => \'clearance/sessions#destroy\', :via => :delete, :as => \'sign_out\'

            sign_in        /login(.:format)                        {:action=>\"new\", :controller=>\"clearance/sessions\"}
           sign_out DELETE /logout(.:format)                       {:action=>\"destroy\", :controller=>\"clearance/sessions\"}

          passwords POST   /passwords(.:format)                    {:action=>\"create\", :controller=>\"clearance/passwords\"}
       new_password GET    /passwords/new(.:format)                {:action=>\"new\", :controller=>\"clearance/passwords\"}
            session POST   /session(.:format)                      {:action=>\"create\", :controller=>\"clearance/sessions\"}
        new_session GET    /session/new(.:format)                  {:action=>\"new\", :controller=>\"clearance/sessions\"}
                    DELETE /session(.:format)                      {:action=>\"destroy\", :controller=>\"clearance/sessions\"}
      user_password POST   /users/:user_id/password(.:format)      {:action=>\"create\", :controller=>\"clearance/passwords\"}
 edit_user_password GET    /users/:user_id/password/edit(.:format) {:action=>\"edit\", :controller=>\"clearance/passwords\"}
                    PUT    /users/:user_id/password(.:format)      {:action=>\"update\", :controller=>\"clearance/passwords\"}
              users POST   /users(.:format)                        {:action=>\"create\", :controller=>\"clearance/users\"}
           new_user GET    /users/new(.:format)                    {:action=>\"new\", :controller=>\"clearance/users\"}
            sign_up        /sign_up(.:format)                      {:action=>\"new\", :controller=>\"clearance/users\"}
            sign_in        /sign_in(.:format)                      {:action=>\"new\", :controller=>\"clearance/sessions\"}
           sign_out DELETE /sign_out(.:format)                     {:action=>\"destroy\", :controller=>\"clearance/sessions\"}