Update README.md

2015-12-16 00:15:29 -08:00 · 2015-12-16 00:15:29 -08:00 · abf436b2bb
--- a/README.md
+++ b/README.md
@ -61,7 +61,7 @@ npm install

 Run the demo:

-```
+```bash
 node examples/letsencrypt.js user@example.com example.com
 ```