diff --git a/mix.exs b/mix.exs
index 0ba916f..5264ab6 100644
--- a/mix.exs
+++ b/mix.exs
@@ -18,7 +18,7 @@ defmodule EasySSL.MixProject do
 
   def application do
     [
-      extra_applications: [:logger]
+      extra_applications: [:logger, :private_key]
     ]
   end