ASP.Net Core and app.settings

Got a question from a colleague on how to handle different app.settings in ASP.Net core 1.1. When debugging in VS the command prompt shows that the ASP.Net Core web application is started in Development. So the question is how to use this to supply different app.settings on different environments.

A quick look in the documentation show that the recommended way to handle app.settings.json is by different files for different environments. 

https://docs.microsoft.com/en-us/aspnet/core/fundamentals/configuration/?tabs=basicconfiguration#configuration-by-environment