feat(app): add a demo mode

app/apps/common/decorators/demo.py

@@ -0,0 +1,15 @@
+from functools import wraps
+
+from django.conf import settings
+from django.core.exceptions import PermissionDenied
+
+
+def disabled_on_demo(view):
+    @wraps(view)
+    def _view(request, *args, **kwargs):
+        if settings.DEMO and not request.user.is_superuser:
+            raise PermissionDenied
+
+        return view(request, *args, **kwargs)
+
+    return _view