chore: add application module

mix.exs

@@ -8,7 +8,7 @@ defmodule Exproj.MixProject do
       elixir: "~> 1.18",
       start_permanent: Mix.env() == :prod,
       deps: deps(),
-      aliases: aliases(),
+      aliases: aliases()
     ]
   end
 
@@ -20,6 +20,8 @@ defmodule Exproj.MixProject do
   def application do
     [
       extra_applications: [:logger],
+      env: [],
+      mod: {Exproj.Application, []}
     ]
   end