anchor.diff:    (if (null login-user)
         (render #P"sessions/new.html")
         (progn
  -        (setf (gethash :user-id *session*) (object-id login-user))
  +        (log-in login-user)
           (redirect (format nil  "/users/~A" (gethash :user-id *session*))))))
   
   (defroute ("/logout" :method :DESTROY) ()
  
positive.code:   (setf (gethash :user-id *session*) nil)
    (setf *current-user* nil))
  
  
  ;;
  ;; Error pages
  
negative.code:   (when (valid-user params)
      (if (gethash :user-id *session*)
          (reset-current-user))
      (log-in (create-user params))
      (redirect (format nil "/users/~A" (object-id (current-user)))))
    (redirect "/users/new"))
  
  