Support pirsch.io for analytics (alshedivat#2513)

Author: garywei944

_config.yml

@@ -121,6 +121,7 @@ contact_note: >
 # and follow the instructions for Google Sites. You will need to create a Google Analytics property and copy the Google tag ID.
 google_analytics: # your Google Analytics measurement ID (format: G-XXXXXXXXXX)
 cronitor_analytics: # cronitor RUM analytics site ID (format: XXXXXXXXX)
+pirsch_analytics: # your Pirsch analytics site ID (length 32 characters)
 
 # For Google Search Console, see https://support.google.com/webmasters/answer/9008080?hl=en#meta_tag_verification&zippy=%2Chtml-tag
 google_site_verification: # your google-site-verification ID (Google Search Console)
@@ -409,6 +410,7 @@ lazy_loading_images: true # enables lazy loading of images (recommended)
 
 enable_google_analytics: false # enables google analytics
 enable_cronitor_analytics: false # enables cronitor RUM analytics
+enable_pirsch_analytics: false # enables Pirsch analytics (https://pirsch.io/)
 enable_google_verification: false # enables google site verification
 enable_bing_verification: false # enables bing site verification
 enable_masonry: true # enables automatic project cards arrangement

_includes/scripts/analytics.liquid

@@ -22,3 +22,11 @@
     cronitor('config', { clientKey: '{{site.cronitor_analytics}}' });
   </script>
 {% endif %}
+{% if site.enable_pirsch_analytics %}
+  <script
+    defer
+    src="https://api.pirsch.io/pa.js"
+    id="pianjs"
+    data-code="{{ site.pirsch_analytics }}"
+  ></script>
+{% endif %}