I can\'t seem to find a way to make T4 templates in VS 2015 RTM, in an ASP.NET 5 (vNext) project.
I even installed the T4 toolbox for Visual Studio 2015 extension, b
If you watch Julie Lerman's pluralsight video: http://www.pluralsight.com/courses/entity-framework-7-looking-ahead she addresses this. There are no plans as of now to remove the T4 templates in upcoming versions of Visual Studio but they didn't make it in for the release. You code always run the reverse engineer tool on your database and go with a code first approach and switch back later (though I don't know why you would in my opinion) but that would be a work around until there is more information on the T4 templates in current VS versions.