Fixed: Add missing index to improve book import performance

src/NzbDrone.Core/Datastore/Migration/015_fix_indexes.cs

@@ -0,0 +1,17 @@
+using FluentMigrator;
+using NzbDrone.Core.Datastore.Migration.Framework;
+
+namespace NzbDrone.Core.Datastore.Migration
+{
+    [Migration(15)]
+    public class FixIndexes : NzbDroneMigrationBase
+    {
+        protected override void MainDbUpgrade()
+        {
+            Delete.Index().OnTable("Books").OnColumn("AuthorId");
+            Delete.Index().OnTable("Books").OnColumns("AuthorId", "ReleaseDate");
+
+            Create.Index().OnTable("Editions").OnColumn("BookId");
+        }
+    }
+}