update rev proxy example

examples/nginx.conf

@@ -8,10 +8,11 @@ server {
   }
 
   location @proxy_to_app {
-    proxy_pass http://unix:/home/hydro/hydro.sock;
+    proxy_pass http://localhost:8888;
     proxy_http_version 1.1;
     proxy_set_header Upgrade $http_upgrade;
     proxy_set_header Connection $connection_upgrade;
+    proxy_set_header X-Real-Host $host;
     proxy_set_header X-Forwarded-For $remote_addr;
   }
 }