Add configuration to appsettings.json with nuget package

I have created a nuget package where I am in need of adding a section to appsettings.json, or add my own configuration file that is copied into the application, but I am unable to figure out how.

I want this:

{"mysection" :   { "value1": "value, "value2": "value"  }}

to be added to the configuration file, or a file containing this to be copied when downloading the nuget package. We are using Visual Studio Team Services to build and host the nuget packages.