Need two backslashes in regex string.

Author: Jim Menard

elixir-mode.el

@@ -562,9 +562,9 @@ Argument END End of the region."
 
 ;;;###autoload
 (progn
-  (add-to-list 'auto-mode-alist '("\\.elixir\'" . elixir-mode))
-  (add-to-list 'auto-mode-alist '("\\.ex\'" . elixir-mode))
-  (add-to-list 'auto-mode-alist '("\\.exs\'" . elixir-mode)))
+  (add-to-list 'auto-mode-alist '("\\.elixir\\'" . elixir-mode))
+  (add-to-list 'auto-mode-alist '("\\.ex\\'" . elixir-mode))
+  (add-to-list 'auto-mode-alist '("\\.exs\\'" . elixir-mode)))
 
 (provide 'elixir-mode)
 ;;; elixir-mode.el ends here