If you have a custom or private NuGet feed, it is recommended that you use a
NuGet.config file in your repository. It will be used by NuKeeper, and by other tools. You can specify a list of NuGet sources on the command line. e.g.
nukeeper update --source https://api.nuget.org/v3/index.json --source http://packages.mycompany.com/nugetfeed
If you override this, you can chose to include the global public
api.nuget.org feed or not. You may not need to, if your internal feed proxies the nuget.org feed.
The order of precedence is:
1) sources on command line
3) Default public NuGet.org feed