Support for configuration files and command-line arguments

[dhillondeep]

After looking at this project briefly, I see that there are many environment variables that the user can set. Viper makes configurations a breeze and also provides many great features out of the box such a using configuration files along with environment variables. It makes a lot of sense to switch to viper. While using viper, you can also utilize Cobra which will make the cli great! I would love to know your thoughts on this?

[cainlevy]

Configuration files and command line flags have been on my wishlist since launch! I think those formats provide much better opportunities for discovering and documenting options.

I find it hard to escape ENV vars in production, personally.

[dhillondeep]

viper can pretty much provide all that without taking any functionality away. A user could choose to provide values by env, config files or some hybrid approach. This helps in allowing customization based on the environment being used. I will look at codebase in more detail and see if it is not too much work and maybe I can create a PR for you to review!