Move source code into "Source" folder

Source/DataLayer/Configurations/SeriesConfig.cs

@@ -0,0 +1,19 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace DataLayer.Configurations
+{
+    internal class SeriesConfig : IEntityTypeConfiguration<Series>
+    {
+        public void Configure(EntityTypeBuilder<Series> entity)
+        {
+            entity.HasKey(s => s.SeriesId);
+            entity.HasIndex(s => s.AudibleSeriesId);
+
+            entity
+                .Metadata
+                .FindNavigation(nameof(Series.BooksLink))
+                .SetPropertyAccessMode(PropertyAccessMode.Field);
+        }
+    }
+}