django.db.utils.OperationalError: FATAL: database “dbname” does not exist

Question

I'm trying to deploy my Django app on docker ,but when i run the container it shows:

psycopg2.OperationalError: FATAL: database "NUTEK" does not exist

my docker-compose.yml file:

version: '2.1' 
services:
  web:
    restart: always
    build: ./web
    expose:
      - "8000"
    links:
      - postgres:postgres
      - redis:redis
    volumes:
      - /usr/src/app
      - /usr/src/app/static


  nginx:
    restart: always
    build: ./nginx/
    ports:
      - "80:80"
    volumes:
      - /www/static

    links:
      - web:web

  postgres:
    restart: always
    image: postgres:10.6
    ports:
      - "5432:5432"

  redis:
    restart: always
    image: redis:latest
    ports:
      - "6379:6379"

my Dockerfile:

FROM python:3.6.6-onbuild
CMD ["python", "manage.py","run server"]

the settings.py file of my Django app:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'NUTEK',
        'USER': 'postgres',
        'PASSWORD': 'root',
        'HOST': 'postgres',
        'PORT': '5432',
    }
}

my .env file:

SECRET_KEY='secret'
DB_NAME=NUTEK
DB_USER=postgres
DB_PASS=root
DB_SERVICE=postgres
DB_PORT=5432

i've searched on issues on the github repository of docker-libraries/postgres and stackoverflow and i found that i should create the database :

docker run -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=root -e POSTGRES_DB=NUTEK postgres 

but that didn't help also ,hope someone can help .