init.el

(if (>= emacs-major-version 24)
    (electric-pair-mode t)
  ;; Setup the alternative manually.
  (progn
    ;; ...
))

(require 'ruby-electric)
(add-hook 'ruby-mode-hook
  '(lambda ()
     (ruby-electric-mode t)
     ;; Want to avoid some weird completions arising from
     ;; the use of ruby-electric.el and electric-pair-mode.
     (when (>= emacs-major-version 24)
       (set (make-local-variable 'electric-pair-mode) nil))))