Updated readme and added new sample project

samples/ReadmeSample/ApplicationDbContext.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Security.Cryptography.X509Certificates;
+using System.Text;
+using System.Threading.Tasks;
+using EntityFrameworkCore.Projections.Extensions;
+using Microsoft.EntityFrameworkCore;
+using ReadmeSample.Entities;
+
+namespace ReadmeSample
+{
+    public class ApplicationDbContext : DbContext
+    {
+        public DbSet<User> Users { get; set; }
+        public DbSet<Product> Products { get; set; }
+        public DbSet<Order> Orders { get; set; }
+
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            optionsBuilder.UseSqlServer("Server=(localdb)\\MSSQLLocalDB;Database=ReadmeSample;Trusted_Connection=True");
+            optionsBuilder.UseProjections();
+        }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            modelBuilder.Entity<OrderItem>().HasKey(x => new { x.OrderId, x.ProductId });
+        }
+
+    }
+}