adding mongo-express

[christofer-f]

Hi!

Thanks for this repo. It is very informative.
I was wondering if it is possible to add mongo-express to admin the database.
I tried to add this snippet of code to the compose file but failed.

  mongo-express:
    image: mongo-express
    container_name: "mongo-express"
    restart: always
    ports:
      - 8081:8081
    networks:
      - backend