nginx_expire_headers.conf

server {
    listen       80;
    server_name  localhost;
    root /home/kafka/apps/cootweet/public;   # <--- be sure to point to 'public'!
    passenger_enabled on;

  location ~* \.(ico|css|js|gif|jp?g|png)(\?[0-9]+)?$ {
    expires max;
    break;
  }
}