Enable gzip in prod

lib/music_library_web/endpoint.ex

@@ -21,12 +21,13 @@ defmodule MusicLibraryWeb.Endpoint do
 
   # Serve at "/" the static files from "priv/static" directory.
   #
-  # You should set gzip to true if you are running phx.digest
-  # when deploying your static files in production.
+  # When code reloading is disabled (e.g., in production),
+  # the `gzip` option is enabled to serve compressed
+  # static files generated by running `phx.digest`.
   plug Plug.Static,
     at: "/",
     from: :music_library,
-    gzip: false,
+    gzip: not code_reloading?,
     only: MusicLibraryWeb.static_paths()
 
   if Code.ensure_loaded?(Tidewave) do