Add rainbow-delimiters to prog-mode

Cask

@@ -5,3 +5,4 @@
 (depends-on "dockerfile-mode")
 (depends-on "htmlize")
 (depends-on "org-plus-contrib")
+(depends-on "rainbow-delimiters")

publish.el

@@ -28,6 +28,9 @@
 (require 'ox-rss)
 (require 'subr-x)
 (require 'dockerfile-mode)
+(require 'rainbow-delimiters)
+
+(add-hook 'prog-mode-hook 'rainbow-delimiters-mode)
 
 (defun publish-calculate-reading-time (buffer)
   "Calculate the amount of minutes it would take to read the contents of BUFFER."