AspNet "Visual Studio Code" for Mac, how to add a local DLL dependency to project.json manually or using DNX, DNU?

Question

There sided DLL, which is stored as a normal image something.dll(i.e., is not part of the repository and is not published using repository) and for this example the code DLL, Program.cs. The entire project is a simple console application created with yo.

How to add dependency on this dll to project.json?

I would like to add the dependency manually to project.jsonwith a link to the local file, or I would like to know how to add the file to the local repository (which is stored in the folder .dnx, I suppose) and then use it in package.json.

My installation ASP.NET Visual Studio Codeuses dnxand dnu. Thank you in advance.