First of all, Postgres is a rock solid database and runs on all platforms. Marten allows, in a core clr .Net app to handover a POCO to the database with no additional ceremony whatsoever. That's true elegance. Full Stop :)
The project is a good starting point for a full PostGres/Marten/WebApi based backend with clean DI based on autofac.
This project uses preview3 of dotnet core clr 1.1. Make sure you have installed this sdk.