Add dockerfile

Dockerfile

+FROM python:3.6-alpine
+
+RUN mkdir -p /usr/src/app
+WORKDIR /usr/src/app
+
+COPY requirements.txt /usr/src/app/
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY . /usr/src/app
+
+# Expose the Flask port
+EXPOSE 5000
+
+ENV FLASK_APP=main.py
+CMD [ "python", "-m", "flask", "run", "--port", "5000", "--host", "0.0.0.0" ]