Nginx server configuration for use with Unicorn

nginx.conf

worker_processes 1;
user nobody nogroup; 
pid /tmp/nginx.pid;
error_log /tmp/nginx.error.log;
events {
  worker_connections 1024; 
  accept_mutex off; 
}
http {
  default_type application/octet-stream;
  access_log /tmp/nginx.access.log combined;
  sendfile on;
  tcp_nopush on; 
  tcp_nodelay off; 
  gzip on;
  gzip_http_version 1.0;
  gzip_proxied any;
  gzip_min_length 500;
  gzip_disable "MSIE [1-6]\.";
  gzip_types text/plain text/html text/xml text/css
             text/comma-separated-values
             text/javascript application/x-javascript
             application/atom+xml;
  upstream app_server {
    server unix:/tmp/.sock fail_timeout=0;
  }
  server {
    client_max_body_size 4G;
    server_name _;
    keepalive_timeout 5;

     ############################################################################
     # Edit this path to point to the 'public' folder of your rails app
     # This feels a little counter intuitive because this root path is NOT the
     # root directory of your rails app, but the public directory of the 
     # rails app root directory. But that's how it is!
     # Don't forget the semicolon at the end of the line!!!
     ############################################################################
    root /var/www/testapp/public;

    try_files $uri/index.html $uri.html $uri @app;
    location @app {
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_redirect off;
      proxy_pass http://app_server;
    }
    error_page 500 502 503 504 /500.html;
    location = /500.html {
        #################################
        # Edit here too!
        #################################
	root /var/www/testapp/public;
    }
  }
}