Track asset cache inserted_at

lib/music_library/assets/cache.ex

@@ -1,15 +1,16 @@
 defmodule MusicLibrary.Assets.Cache do
   def new do
-    :ets.new(__MODULE__, [:named_table, :public, read_concurrency: true])
+    :ets.new(__MODULE__, [:named_table, :public, :compressed, read_concurrency: true])
   end
 
   def set(payload, format, content) do
-    :ets.insert(__MODULE__, {{payload, format}, content})
+    inserted_at = DateTime.utc_now() |> DateTime.to_unix()
+    :ets.insert(__MODULE__, {{payload, format}, inserted_at, content})
   end
 
   def get(payload, format) do
     case :ets.lookup(__MODULE__, {payload, format}) do
-      [{{^payload, ^format}, content}] -> {:found, content}
+      [{{^payload, ^format}, _inserted_at, content}] -> {:found, content}
       [] -> :not_found
     end
   end