Add aspnetcore-tools to build NuGet.config

build/NuGet.config

@@ -4,5 +4,6 @@
     <clear />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
     <add key="aspnetmaster" value="https://dotnet.myget.org/f/aspnetcore-master/api/v3/index.json" />
+    <add key="aspnetcore-tools" value="https://dotnet.myget.org/F/aspnetcore-tools/api/v3/index.json" />
   </packageSources>
 </configuration>