Update the SyncWorker to add logging.

lib/decentralised_book_index/sync/sync_workers/sync_worker.ex

@@ -6,8 +6,16 @@ defmodule DecentralisedBookIndex.SyncWorker do
 
   require Logger
 
+  alias DecentralisedBookIndex.SyncTasks.SyncServerTask
+
   @impl Oban.Worker
   def perform(%Oban.Job{args: args} = job) do
-    SyncServerTask.sync_all()
+    Logger.info("The cron job (#{job.id}) run SyncServerTask at #{DateTime.utc_now()} with args: #{inspect(args)}")
+
+    result = SyncServerTask.sync_all()
+
+    Logger.info("The cron job (#{job.id}) is done.")
+
+    result
   end
 end