Add plausible stats for jupyter.org (#296)

Author: jasongrout

_config.yml

@@ -28,5 +28,7 @@ html:
     </p>
 
 sphinx:
+  local_extensions:
+    _plausible: .
   config:
     html_show_copyright: false

_plausible.py

@@ -0,0 +1,23 @@
+"""Sphinx extension to add Plausible analytics to Jupyter Book."""
+
+
+def setup(app):
+    """Add Plausible analytics scripts to the site."""
+    # Add the external Plausible script for jupyter.org
+    app.add_js_file(
+        "https://plausible.io/js/pa-B75UO5--FNXYQSG7GBWkf.js",
+        loading_method="async"
+    )
+
+    # Add the inline initialization script
+    plausible_init = """
+  window.plausible=window.plausible||function(){(plausible.q=plausible.q||[]).push(arguments)},plausible.init=plausible.init||function(i){plausible.o=i||{}};
+  plausible.init({hashBasedRouting:true})
+"""
+    app.add_js_file(None, body=plausible_init)
+
+    return {
+        'version': '0.1',
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+    }