use "C-j" & "C-k" in ivy

lisp/completion.el

@@ -91,6 +91,13 @@
         )
 
   (global-set-key "\C-s" 'swiper)
+
+  (dolist (map (list ivy-minibuffer-map
+                     ivy-switch-buffer-map
+                     ivy-reverse-i-search-map))
+    (define-key map (kbd "C-j") 'ivy-next-line)
+    (define-key map (kbd "C-k") 'ivy-previous-line))
+
   :bind
   (("C-c s s" . 'swiper)
    ("C-c s p" . 'user/counsel-search-project)