Document new reading time variable in _config.yml

Author: mmistakes

theme-setup.md

@@ -189,6 +189,10 @@ The rest is just your average Jekyll config settings. Nothing too crazy here...
 
 For the most part you can leave these as is since the author/owner details are pulled from `_config.yml`. That said you'll probably want to customize the copyright stuff in `footer.html` to your liking.
 
+### Reading Time
+
+On by default. To turn off remove `reading_time` from `_config.yml. Default words per minute is set at 200 and can changed by updating `words_per_minute` in `_config.yml`.
+
 ### Adding Posts and Pages
 
 There are two main content layouts: `post.html` (for posts) and `page.html` (for pages). Both have support for large **feature images** that span the full-width of the screen, and both are meant for text heavy blog posts (or articles).