Exclude vendor files from jekyll config

This is needed to make jekyll work with bundler.

See jekyll/jekyll#2938

Signed-off-by: John Else <[email protected]>

Author: johnelse

_config.yml

@@ -3,3 +3,4 @@ redcarpet:
   extensions: ["no_intra_emphasis", "fenced_code_blocks", "autolink", "tables", "with_toc_data"]
 highlighter: pygments
 permalink: /:title
+exclude: [vendor]