How much RAM is needed to host discourse along with other services?

Installation Hosting
4

Here is the docker-compose file. I had to remove some of the images links since I cannot post more than 2, however, this should be good. Where would I place the DB buffer environment variable?

version: '2'
services:
  nginx:
    image: ''
    #image: 'itshady/nginx'
    ports:
      - '80:80'
    depends_on:
      - discourse
  intellectus:
    image: '
#    image: 'itshady/intellectus'
    ports:
      - '90:80'
  postgresql:
    image: ''
    environment:
      - ALLOW_EMPTY_PASSWORD=yes
    volumes:
      #- './data/postgresql:/bitnami/postgresql'
      - 'postgresql_data:/bitnami/postgresql'
  redis:
    image: ''
    environment:
      - ALLOW_EMPTY_PASSWORD=yes
    volumes:
      - 'redis_data:/bitnami'
  discourse:
    image: 'docker.io/bitnami/discourse:2-debian-10'        #2-debian-10
    ports:
      - '100:3000'
    depends_on:
      - postgresql
      - redis
    volumes:
      - './data/discourse:/bitnami'
    environment:
      - POSTGRESQL_HOST=postgresql
      - POSTGRESQL_ROOT_USER=postgres
      - POSTGRESQL_CLIENT_CREATE_DATABASE_NAME=bitnami_application
      - POSTGRESQL_CLIENT_CREATE_DATABASE_USERNAME=bn_discourse
      - POSTGRESQL_CLIENT_CREATE_DATABASE_PASSWORD=bitnami1
      - DISCOURSE_POSTGRESQL_NAME=bitnami_application
      - DISCOURSE_POSTGRESQL_USERNAME=bn_discourse
      - DISCOURSE_POSTGRESQL_PASSWORD=bitnami1
      #- DISCOURSE_HOSTNAME=forums.intellectus.ca
      - DISCOURSE_HOSTNAME=${FORUM_URL}
      - DISCOURSE_EMAIL=
      - SMTP_HOST=
      - SMTP_PORT=
      - SMTP_USER=
      - SMTP_PASSWORD=
  sidekiq:
    image: 'docker.io/bitnami/discourse:2-debian-10'
    depends_on:
      - discourse
    volumes:
      - './data/discourse:/bitnami'
    command: 'nami start --foreground discourse-sidekiq'
    environment:
      - DISCOURSE_POSTGRESQL_NAME=bitnami_application
      - DISCOURSE_POSTGRESQL_USERNAME=bn_discourse
      - DISCOURSE_POSTGRESQL_PASSWORD=bitnami1
      - DISCOURSE_HOST=discourse
      - DISCOURSE_PORT=3000
      #- DISCOURSE_HOSTNAME=forums.intellectus.ca
      - DISCOURSE_HOSTNAME=${FORUM_URL}
      - SMTP_HOST=
      - SMTP_PORT=
      - SMTP_USER=
      - SMTP_PASSWORD=
volumes:
  postgresql_data:
    driver: local
#    external: true
  redis_data:
    driver: local
#    external: true
  discourse_data:
    driver: local
#    external: true