set max age to 12 hours

nginx/cfg

@@ -26,7 +26,6 @@ server {
 
   root /var/www/html;
 
-  # Add index.php to the list if you are using PHP
   index index.html;
 
   server_name _;
@@ -36,6 +35,7 @@ server {
     # as directory, then fall back to displaying a 404.
     try_files $uri $uri/ =404;
     add_header "Access-Control-Allow-Origin" "*";
+    add_header "Cache-Control" "max-age=43200";
     # Remove CORS.
     if ($request_method = "OPTIONS") {
       add_header "Access-Control-Allow-Origin" "*";