nginx.conf

user nginx;
worker_processes 1;
error_log /var/log/nginx/error.log;
pid /var/run/nginx.pid;
events {
  worker_connections 1024;
}

http {
  include /etc/nginx/mime.types;
  default_type application/octet-stream;
  server_tokens off;

  upstream unicorn {
    server unix:/tmp/unicorn.[app].sock fail_timeout=0;
  }

  server {
    listen 80 default deferred;
    root [app_home]/public;

    try_files $uri/index.html $uri @unicorn;
    location @unicorn {
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_redirect off;
      proxy_pass http://unicorn;
    }

    error_page 500 502 503 504 /500.html;
    client_max_body_size 4G;
    keepalive_timeout 10;
  }
}