add distillery for releases

mix.exs

@@ -25,7 +25,8 @@ defmodule Dough.MixProject do
       {:cowboy, "~> 2.4.0"},
       {:plug, "~> 1.5"},
       {:dns, "~> 2.1.0"},
-      {:cachex, "~> 3.0.3"}
+      {:cachex, "~> 3.0.3"},
+      {:distillery, "~> 2.0"}
     ]
   end
 end