Add docker config for example app

docker-compose.yml

@@ -0,0 +1,25 @@
+version: "3.3"
+volumes:
+  db_data: {}
+
+services:
+  mongo:
+    image: mongo:4.4
+    volumes:
+      - db_data:/data/db/
+    ports:
+      - 27017:27017
+    restart: always
+
+  flask:
+    build:
+      context: .
+      dockerfile: ./example_app/compose/flask/Dockerfile
+    depends_on:
+      - mongo
+    command: python ./example_app/app.py
+    ports:
+      - 8000:8000
+    volumes:
+      - ./:/flask_mongoengine
+    restart: always

example_app/compose/flask/Dockerfile

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+FROM python:3.7-slim as dev
+
+ENV PYTHONUNBUFFERED 1
+RUN groupadd -r flask && useradd -r -g flask flask
+COPY --chown=flask . /flask_mongoengine
+RUN pip install --upgrade pip  \
+    && pip install -r /flask_mongoengine/requirements.txt  \
+    && pip install -e /flask_mongoengine
+WORKDIR /flask_mongoengine