Only include analytics when in production environment

Author: bradygm

_includes/head.html

@@ -47,7 +47,7 @@
   {% endif %}
 
     {% seo %}
-    {%- if site.google_analytics -%}
+    {%- if site.google_analytics and jekyll.environment == "production" -%}
       {%- include google-analytics.html -%}
     {%- endif -%}
     {%- include head-scripts.html -%}