Django, Docker, and Pipenv - Error adding new packages, not transfering from container to local volume

Question

I'm following allong with the book 'Django for Professionals' but I run into what seems like the same problem the author of the book experienced in this quastion. I'm using it on windows so with Docker-toolbox and what seems to happen is that after running

    docker-compose exec web pipenv install psycopg2-binary==2.8.4

the Pipfile.lock has changed inside the container, but it doesn't transfer/sync this to my local files, it seems as if the 'volume' lost track of the file?

I opened the Pipfile.lock inside the container to verify that it indeed added psycopg2, which it did, but when I docker-compose down it is not in my local Pipfile.lock and thus lost the next time when I use docker-compose up -d --build

The only solution I have found myself so far is to copy the file over from the running docker container to my local folder with which is far from ideal

    docker cp web:/code/Pipfile.lock . 

output from docker-compose exec web pipenv install psycopg2-binary==2.8.4

    E:\Documenten\websites\code\postgresql>docker-compose exec web pipenv install                                 
    psycopg2-binary==2.8.4
    Installing psycopg2-binary==2.8.4…
    Adding psycopg2-binary to Pipfile's [packages]…
    ✔ Installation Succeeded
    Installing dependencies from Pipfile.lock (a06fa0)…
       ▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉ 5/5 — 00:00:09
    To activate this project's virtualenv, run pipenv shell.
    Alternatively, run a command inside the virtualenv with pipenv run.

docker-compose.yml

    version: '3.7'

    services:
      web:
        build: .
        command: python manage.py runserver 0.0.0.0:8000
        volumes:
          - .:/code
        ports:
          - 8000:8000
        depends_on:
          - db
      db:
        image: postgres:11
        environment:
          - "POSTGRES_HOST_AUTH_METHOD=trust"

Dockerfile

    # Pull base image
    FROM python:3.7-slim

    # Set environment variables
    ENV PYTHDONTWRITEBYTECODE 1
    ENV PYTHONUNBUFFERED 1

    # Set work directory
    WORKDIR /code

    # Install dependencies
    COPY Pipfile Pipfile.lock /code/
    RUN pip install pipenv && pipenv install --system

    # Copy project
    COPY . /code/

    # Make executable
    RUN chmod +x /code/manage.py