Hammock nuget installation

Disclaimer: I'm new to .NET, nuget, windows store applications and so on.

I'm trying to follow this tutorial to create a Twitter-based universal windows app.

But I can't install Hammock, it keeps getting me:

Install failed. Rolling back...
Install-Package : Impossibile installare il pacchetto 'Hammock 1.3.1'. Si sta tentando di eseguire l'installazione in un progetto destinato a   '.NETCore,Version=v4.5.1', ma il 
pacchetto non contiene riferimenti ad assembly o file di dati compatibili con il framework. Per ulteriori informazioni, contattare l'autore del pacchetto.
At line:1 char:1
+ Install-Package Hammock
+ ~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : NotSpecified: (:) [Install-Package], InvalidOperationException
+ FullyQualifiedErrorId :     NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand

The italian part say something like "I can't install Hammock because the package doesn't contain references to assembly or files compatible with the framework".

Thanks for the help.