worker_processes 1;
error_log stderr;
pid nginx.pid;
daemon off;

events {
	worker_connections 768;
} 

http {
	include mime.types;
	server {
		listen <%= ENV['PORT'] %>;
		server_name  _;
		root /app/www;
		index index.html;
	}
} 

worker_processes 1;
error_log stderr;
pid nginx.pid;
daemon off;
types_hash_max_size 2048;

events {
	worker_connections 768;
} 

http {
	include mime.types;
	server {
		listen <%= ENV['PORT'] %>;
		server_name  _;
		root /app/www;
		index index.html;
	}
} 

Set types_hash_max_size large enough for default mime.types
Set types_hash_max_size large enough for default mime.types