Run Repo vacuum via Oban scheduled job

This way if there's any resource contention to obtain a db connection,
Oban can manage retries.

config/config.exs

@@ -85,7 +85,9 @@ config :music_library, Oban,
      crontab: [
        # every 12 hours
        {"0 */12 * * *", MusicLibrary.Worker.ApplyScrobbleRules},
-       {"0 */12 * * *", MusicLibrary.Worker.PruneAssetCache}
+       {"0 */12 * * *", MusicLibrary.Worker.PruneAssetCache},
+       # every day at 3 am,
+       {"0 3 * * *", MusicLibrary.Worker.RepoVacuum}
      ]}
   ]
 

lib/music_library/worker/repo_vacuum.ex

@@ -0,0 +1,10 @@
+defmodule MusicLibrary.Worker.RepoVacuum do
+  use Oban.Worker, queue: :heavy_writes, max_attempts: 3
+
+  require Logger
+
+  @impl Oban.Worker
+  def perform(_) do
+    MusicLibrary.Repo.vacuum()
+  end
+end