diff --git a/nginx.conf b/nginx.conf
index 06a546e..fb218d7 100644
--- a/nginx.conf
+++ b/nginx.conf
@@ -17,6 +17,7 @@ http {
     lua_code_cache ${{CODE_CACHE}};
 
     location / {
+      set $_url "";
       default_type text/html;
       content_by_lua '
         require("lapis").serve("app")