config.yaml or config.yml

[StephenKing]

Hi thanks for that interesting project!

I noticed in docs and code that both file extensions (yaml and yml) are used. Without and argument, it seems config.yml is used. Took me a while to figure this out, as there is no error message.

Let me know, if I should file a PR to align file extensions...

[yu-re-ka]

Hi, without any argument, no config file is used and the configuration is taken entirely from environment variables.
Since there is no discrimination between .yml and .yaml file endings in the code, I consider this a very low priority issue, but feel free to open a PR and standardize it either way.