Migrate activity db to EF Core

Jellyfin.Server.Implementations/Migrations/DesignTimeJellyfinDbFactory.cs

@@ -0,0 +1,20 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Design;
+
+namespace Jellyfin.Server.Implementations.Migrations
+{
+    /// <summary>
+    /// The design time factory for <see cref="JellyfinDb"/>.
+    /// This is only used for the creation of migrations and not during runtime.
+    /// </summary>
+    internal class DesignTimeJellyfinDbFactory : IDesignTimeDbContextFactory<JellyfinDb>
+    {
+        public JellyfinDb CreateDbContext(string[] args)
+        {
+            var optionsBuilder = new DbContextOptionsBuilder<JellyfinDb>();
+            optionsBuilder.UseSqlite("Data Source=jellyfin.db");
+
+            return new JellyfinDb(optionsBuilder.Options);
+        }
+    }
+}