Add navigation highlighting.

app/templates/base.html.j2

@@ -193,6 +193,12 @@
           document.getElementById("new-job"),
           {"coverTrigger": false}
         );
+        var entry;
+        for (entry of document.querySelectorAll("#slide-out a:not(.subheader)")) {
+          if (entry.href === window.location.href) {
+            entry.parentNode.classList.add("active");
+          }
+        }
         {% for message in get_flashed_messages() %}
         M.toast({html: '{{ message }}'})
         {% endfor %}