init_packages.el

(setq el-get-sources
      '((:name package-name)))

(defun sync-packages ()
  "Synchronize packages"
  (interactive)
  (el-get 'sync '(el-get package))
  (add-to-list 'package-archives '("tromey" . "http://tromey.com/elpa/"))
  (add-to-list 'package-archives '("marmalade" . "http://marmalade-repo.org/packages/"))
  (setq my-packages (mapcar 'el-get-source-name el-get-sources))
  (el-get 'sync my-packages))

(if (require 'el-get nil t)
    (sync-packages)
  (url-retrieve
   "https://raw.github.com/dimitri/el-get/master/el-get-install.el"
   (lambda (s)
     (let (el-get-master-branch)
       (end-of-buffer)
       (eval-print-last-sexp)
       (setq el-get-verbose t)
       (sync-packages)))))