Add GA tracking code

Author: thomasleese

config/tech-docs.yml

@@ -13,7 +13,7 @@ header_links:
   Reference: /reference.html
 
 # Tracking ID from Google Analytics (e.g. UA-XXXX-Y)
-ga_tracking_id:
+ga_tracking_id: UA-26179049-13
 
 # Table of contents depth – how many levels to include in the table of contents.
 # If your ToC is too long, reduce this number and we'll only show higher-level