I am trying to docker up my django application using this tutorial.
https://testdriven.io/blog/dockerizing-django-with-postgres-gunicorn-and-nginx/

Technically, I have 2 problems:
1) Cannot connect to the database
2) 502 gateway error

Everything seems to work until i get this error:

nginx-proxy    | nginx.1  *1 connect() failed (111: Connection refused) while connecting to upstream, client: 111.222.333.444, server: www.hello.com, request: "GET /favicon.ico HTTP/2.0", upstream: "http://172.25.0.2:8000/favicon.ico", host: "www.hello.com", referrer: "https://www.hello.com/"

Also, it seems that my web server is unable to detect my postgresql database as it prompts a “waiting for postgres” due to the entrypoint.sh i have provided. I have configured my database using this tutorial:
https://www.digitalocean.com/community/tutorials/how-to-set-up-django-with-postgres-nginx-and-gunicorn-on-ubuntu-20-04

Been stuck with this for a few days! I will attach my code here:

When I run netstat plant:

Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 127.0.0.53:53           0.0.0.0:*               LISTEN      637/systemd-resolve 
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      840/sshd            
tcp        0      0 127.0.0.1:5432          0.0.0.0:*               LISTEN      27204/postgres      
tcp        0      0 127.0.0.1:35449         0.0.0.0:*               LISTEN      19618/containerd    
tcp        0      0 111.222.333.444:22       555.666.777.888:52289    ESTABLISHED 740/sshd: root@nott 
tcp        0   1080 111.222.333.444:22       999.111.222.333:13146    ESTABLISHED 16139/sshd: [accept 
tcp        0    356 111.222.333.444:22       555.666.777.888:52288    ESTABLISHED 32641/sshd: root@pt 
tcp6       0      0 :::22                   :::*                    LISTEN      840/sshd   

docker-compose file:

version: '3.8'

services:
  web:
    container_name: container_name
    build:
      context: ./hello_main
      dockerfile: Dockerfile.prod
    image: hello
    command: gunicorn --timeout 180 hello.wsgi:application --bind 0.0.0.0:8000
    volumes:
      - static_volume:/home/app/web/staticfiles
      - media_volume:/home/app/web/mediafiles
    expose:
      - 8000
    env_file:
      - ./.env
  nginx-proxy:
    container_name: nginx-proxy
    build: ./nginx
    image: nginx-proxy
    restart: always
    ports:
      - 80:80
    volumes:
      - static_volume:/home/app/web/staticfiles
      - media_volume:/home/app/web/mediafiles
      - certs:/etc/nginx/certs
      - html:/usr/share/nginx/html
      - vhost:/etc/nginx/vhost.d
      - /var/run/docker.sock:/tmp/docker.sock:ro
    depends_on:
      - web

volumes:
  static_volume:
  media_volume:
  certs:
  html:
  vhost:

DockerFile stuff works fine.

I also configured settings on nginx based on this tutorial: https://testdriven.io/blog/dockerizing-django-with-postgres-gunicorn-and-nginx/
I did not use the nginx.conf provided by the digitalocean server.

vhost.d/default

server {

    listen 80;

    location / {
        proxy_pass http://www.hello.com;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_redirect off;
    }


location = /favicon.ico { access_log off; log_not_found off; }


location /staticfiles/ {
  alias /home/app/web/staticfiles/;
  add_header Access-Control-Allow-Origin *;
}

location /mediafiles/ {
  alias /home/app/web/mediafiles/;
  add_header Access-Control-Allow-Origin *;
  proxy_read_timeout 300;
  proxy_connect_timeout 300;
  proxy_send_timeout 300; 
}

DockerFile for NGINX:

FROM jwilder/nginx-proxy
COPY vhost.d/default /etc/nginx/vhost.d/default
COPY custom.conf /etc/nginx/conf.d/custom.conf

CUSTOM.CONF FOR NGINX

client_max_body_size 25M;
proxy_connect_timeout       600;
proxy_send_timeout          600;
proxy_read_timeout          600;
send_timeout                600;