Start sessions of last purchase from list

Fixes #19

src/web/tracker/urls.py

@@ -12,6 +12,11 @@ urlpatterns = [
         views.update_session,
         name="update_session",
     ),
+    path(
+        "start-session/<int:purchase_id>",
+        views.start_session,
+        name="start_session",
+    ),
     path(
         "delete_session/by-id/<int:session_id>",
         views.delete_session,