Restore missing migration with amended rollback task

priv/repo/migrations/20250101170610_add_error_tracker.exs

@@ -0,0 +1,11 @@
+defmodule MusicLibrary.Repo.Migrations.AddErrorTracker do
+  use Ecto.Migration
+  def up, do: ErrorTracker.Migration.up(version: 4)
+
+  def down do
+    # Not sure why, but the built-in migration fails, so we're removing things manually
+    drop table(:error_tracker_meta)
+    drop table(:error_tracker_errors)
+    drop table(:error_tracker_occurrences)
+  end
+end