Support for environment variables

[nerdalertdk]

To continue #23

If you are gonna anything big with the config system, please consider support for ENV
it even support a default value.

https://www.geeksforgeeks.org/python-os-getenv-method/

[nerdalertdk]

This would keeping our config file easy to maintain, only have the options we changed

# If HOSTNAME doesn't exist, presume local development and return localhost
print(os.environ.get('HOSTNAME', 'localhost')

https://medium.com/dopplerhq/using-environment-variables-in-python-for-app-configuration-and-secrets-50f01ea1fd3d

[nerdalertdk]

Fixed it and support for this in my docker image so closing this