For Heroku-16 stack and 2.0.0 Preview 2 use:
heroku buildpacks:set https://github.com/jincod/dotnetcore-buildpack
For Heroku-16 stack and .NET Core 1.0.4 (LTS)
heroku buildpacks:set https://github.com/jincod/dotnetcore-buildpack#v1.0.4
For Cedar-14 stack use:
heroku buildpacks:set https://github.com/jincod/dotnetcore-buildpack.git#cedar-14
heroku buildpacks:set https://github.com/jincod/dotnetcore-buildpack
heroku buildpacks:add --index 1 heroku/nodejs