How To Deploy Django App with Nginx, Gunicorn, PostgreSQL and Let’s Encrypt SSL on Ubuntu

Django --> Gunicorn (WSGI server) --> Nginx

From here: 

How To Deploy Django App with Nginx, Gunicorn, PostgreSQL and Let’s Encrypt SSL on Ubuntu

and here: 
How To Set Up Django with Postgres, Nginx, and Gunicorn on Ubuntu 18.04