Docker setup

Readme.md

This is my current setup. How would I scale this with docker-compose:

dcocker-compose scale app=3

docker-compose.yml

app:
  build: ./tile-server
  restart: always
  command: gunicorn wsgi:application -b 0.0.0.0:8080 -w 3
  ports:
    - "8080"

nginx:
  build: ./nginx
  ports:
    - 80:80
  links:
    - app:app

nginx.conf

worker_processes 4;
events {
    worker_connections 1024;
}
http {
    upstream app_servers {
      least_conn;
      server app:8080 weight=10 max_fails=3 fail_timeout=30s;
      server app:8080 weight=10 max_fails=3 fail_timeout=30s;
      server app:8080 weight=10 max_fails=3 fail_timeout=30s;
    }
    server {
        listen 80;
        location / {
            proxy_pass         http://app_servers;
            proxy_redirect     off;
            proxy_set_header   Host $host;
            proxy_set_header   X-Real-IP $remote_addr;
            proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header   X-Forwarded-Host $server_name;
        }
    }
}