Use kramdown

Author: kou

_config.yml

@@ -1,9 +1,12 @@
-markdown: rdiscount
-pygments: true
+markdown: kramdown
 permalink: /:categories/blog/:year/:month/:day/:title.html
 paginate: 5
 url: http://ruby-gettext.github.io
 gettext_version: 3.1.2
 gettext_release_date: 2014-04-24
 locale_version: 2.1.0
 locale_release_date: 2012-12-15
+
+kramdown:
+  enable_coderay: true
+  coderay_line_numbers: table