Add key binding to visit init file and index.org

Inspired by http://emacsredux.com/blog/2013/05/18/instant-access-to-init-dot-el/

lisp/file-manip.el

@@ -11,3 +11,14 @@ buffer is not visiting a file, prompt for a file name."
     (if buffer-file-name
         (find-alternate-file tramp-path)
       (find-file tramp-path))))
+
+(defun gpolonkai/visit-init-file ()
+  "Open the init file."
+  (interactive)
+  (find-file-other-window user-init-file))
+
+(defun gpolonkai/visit-org-index ()
+  "Visit the root of Org-mode notes."
+  (interactive)
+  (find-file-other-window (concat (file-name-as-directory org-directory)
+                                  "index.org")))