Gemfileを保存した時にGrowlで"$ bundle install"しろという注意喚起

init.el

(setq growl-program (executable-find "growlnotify"))
(defun growl (title message &optional app)
  (when growl-program
    (unless app
      (setq app ""))
    (start-process "Growl" "*Growl*" growl-program
                   "-t" title
                   "-m" message
                   "-a" app)))

(require 'ruby-mode)
(add-to-list 'auto-mode-alist '("\\.rb$" . ruby-mode))
(add-to-list 'auto-mode-alist '("[Rr]akefile$" . ruby-mode))
(add-to-list 'auto-mode-alist '("[Gg]emfile$" . ruby-mode))
(add-to-list 'interpreter-mode-alist '("ruby" . ruby-mode))
(add-hook 'after-save-hook
          '(lambda()
             (when (string-match "[Gg]emfile$" buffer-file-name)
               (growl "File has been modified" "Should be bundle install"))))