should support Heroku deployment

[hoatle]

By using a Docker image we can deploy the app easily to a wide range of Docker hosts, especially to Heroku.

[hoatle]

check and refer to these related resources:

• https://github.com/dlofland/heroku-lemp-modified
• https://github.com/iphoting/heroku-buildpack-php-tyler
• https://github.com/heroku/heroku-buildpack-php
• https://devcenter.heroku.com/categories/php

[hoatle]

assigned back to @hoatle