Add functions to generate dominant colors

lib/music_library/worker/generate_dominant_colors.ex

@@ -0,0 +1,12 @@
+defmodule MusicLibrary.Worker.GenerateDominantColors do
+  use Oban.Worker, queue: :heavy_writes, max_attempts: 3
+
+  @impl Oban.Worker
+  def perform(%Oban.Job{args: %{"id" => record_id}}) do
+    record = MusicLibrary.Records.get_record!(record_id)
+
+    with {:ok, updated_record} <- MusicLibrary.Records.generate_dominant_colors(record) do
+      MusicLibrary.Records.notify_update(updated_record)
+    end
+  end
+end