entrypoint.sh: exec: gunicorn: not found - docker

Question

When I build image from Dockerfile:
FROM python:3.8.3-alpine as builder
WORKDIR /usr/src/app
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
RUN apk update \
&& apk add postgresql-dev gcc python3-dev musl-dev jpeg-dev zlib-dev
RUN pip install --upgrade pip
COPY . .
COPY ./requirements.txt .
RUN pip wheel --no-cache-dir --no-deps --wheel-dir /usr/src/app/wheels -r requirements.txt
FROM python:3.8.3-alpine
# create directory for the app user
RUN mkdir -p /home/app
# create the app user
RUN addgroup -S app && adduser -S app -G app
# create the appropriate directories
ENV HOME=/home/app
ENV APP_HOME=/home/app/web
RUN mkdir $APP_HOME
WORKDIR $APP_HOME
# install dependencies
RUN apk update && apk add libpq
COPY --from=builder /usr/src/app/wheels /wheels
COPY --from=builder /usr/src/app/requirements.txt .
RUN pip install --no-cache /wheels/*
# copy entrypoint-prod.sh
COPY ./entrypoint.prod.sh $APP_HOME
# copy project
COPY . $APP_HOME
# chown all the files to the app user
RUN chown -R app:app $APP_HOME
# change to the app user
USER app
# run entrypoint.prod.sh
ENTRYPOINT ["/home/app/web/entrypoint.prod.sh"]
And next run containers. Show me:
web_1 | PostgreSQL started
web_1 | /home/app/web/entrypoint.prod.sh: exec: line 14: gunicorn: not found
entrypoint.prod.sh
#!/bin/sh
if [ "$DATABASE" = "postgres" ]
then
echo "Waiting for postgres..."
while ! nc -z $DB_HOST 5432; do
sleep 0.1
done
echo "PostgreSQL started"
fi
exec "$#"
I also have a problem with nginx because when I enter the address 0.0.0.0:1337 I get an error 502 bad gateway(failed (113: Host is unreachable)). I think it is related to the problem above.
docker-compose.yml
version: '3.7'
services:
nginx:
build: ./nginx
ports:
- "1337:80"
restart: always
networks:
- nginx_network
depends_on:
- web
web:
build:
context: .
dockerfile: Dockerfile
command: gunicorn znajdki.wsgi:application --bind 0.0.0.0:8000
expose:
- "8000"
env_file:
- ./.env.prod
networks:
- nginx_network
- postgres_network
depends_on:
- db
db:
image: postgres
volumes:
- postgres:/var/lib/postgresql/data
env_file:
- ./.env.prod.db
networks:
- postgres_network
networks:
nginx_network:
driver: bridge
postgres_network:
driver: bridge
volumes:
postgres: