Startup.cs

[...]
using MeineApp.Data;
using Microsoft.EntityFrameworkCore;

namespace MeineApp
{
    public class Startup
    {
        [...]
        public void ConfigureServices(IServiceCollection services)
        {
            string connString = Configuration.GetConnectionString("DefaultConnection");
            services.AddDbContext<KcDbContext>(
                options => options.UseSqlite(connString)
            );

            [...]
        }

        [...]
    }
}