gitignore.el

;; creates .gitignore file 
;;
;; added a check, so that if a .gitignore exists already it doesn't overwrite it

(defun gitignore(dir)
  "create .gitignore file in a directory supplied
populating it with the patterns/files"
  (interactive "DDirectory name: ")
  (setq ignore-patterns 
	;; modify patterns/files below as per your need
	'("*~" 
	  "log/*.log"
	  "tmp/**/*"
	  "config/database.yml"  
	  "db/*.sqlite3"))
  (setq .gitignore (concat (file-name-as-directory dir) ".gitignore"))
  (if (file-exists-p .gitignore)
      (progn
	(message "%s exists already, nothing new was added" .gitignore)
	(find-file .gitignore))
    (progn
      (switch-to-buffer .gitignore)
      (while ignore-patterns
	(insert-string (concat (car ignore-patterns) "\n"))
	(setq ignore-patterns (cdr ignore-patterns)))
      (message "%s created" .gitignore))))