title: Docker ENV for Python variables
body: <p>Being new to python &amp; docker, I created a small flask app (test.py) which has two hardcoded values: </p>
  
  <pre><code>username = "test"
  password = "12345"
  </code></pre>
  
  <p>I'm able to create a Docker image and run a container from the following Dockerfile:</p>
  
  <pre><code>FROM python:3.6
  
  RUN mkdir /code  
  WORKDIR /code  
  ADD . /code/  
  RUN pip install -r requirements.txt  
  
  EXPOSE 5000  
  CMD ["python", "/code/test.py"]`
  </code></pre>
  
  <p>How can I create a ENV variable for username &amp; password and pass dynamic values while running containers?</p>