added new projects and some base code for persistence

Tv7Playlist.Data/PlaylistContext.cs

@@ -0,0 +1,23 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace Tv7Playlist.Data
+{
+    public class PlaylistContext : DbContext
+    {
+        public PlaylistContext(DbContextOptions<PlaylistContext> options)
+            : base(options)
+        {
+        }
+
+        public DbSet<PlaylistEntry> PlaylistEntries { get; set; }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            base.OnModelCreating(modelBuilder);
+
+            var entityTypeBuilder = modelBuilder.Entity<PlaylistEntry>();
+            entityTypeBuilder.HasKey(e => e.Id);
+            entityTypeBuilder.HasAlternateKey(e => e.TrackNumber);
+        }
+    }
+}