Docker run application in a volume

In my django docker app i would to use a volume for manage my application file here is my Dockerfile:

FROM python:3.6-alpine
EXPOSE 8000
RUN apk update
RUN apk add --no-cache make linux-headers libffi-dev jpeg-dev zlib-dev
RUN apk add postgresql-dev gcc python3-dev musl-dev

VOLUME /var/lib/cathstudio/data
WORKDIR /var/lib/cathstudio/data

COPY ./requirements.txt .

RUN pip install --upgrade pip
RUN pip install -t /var/lib/cathstudio/data -r requirements.txt
ENV PYTHONUNBUFFERED 1
ENV PYTHONPATH /var/lib/cathstudio/data

COPY . /var/lib/cathstudio/data

ENTRYPOINT python /var/lib/cathstudio/data/manage.py runserver 0.0.0.0:8000

but when i run my app:

docker run -d -it --rm --link postgres:postgres --name=cathstudio myrepo/app_studio:latest

i get

python: can’t open file ‘/var/lib/cathstudio/data/manage.py’: [Errno 2] No such file or directory

the same also if i in my Dockerfile write just ENTRYPOINT python manage.py runserver 0.0.0.0:8000

where is my file wrong? how can i run my app using a volume for storing app files?

So many thanks in advance

Source: StackOverflow