using IDO flex matching for ERC buffers

 (defun rgr/ido-erc-buffer()
    (interactive)
    (switch-to-buffer
     (ido-completing-read "Channel:" 
                          (save-excursion
                            (delq
                             nil
                             (mapcar (lambda (buf)
                                       (when (buffer-live-p buf)
                                         (with-current-buffer buf
                                           (and (eq major-mode 'erc-mode)
                                                (buffer-name buf)))))
                                     (buffer-list)))))))
  
  (global-set-key (kbd "C-c e") 'rgr/ido-erc-buffer)