Mixfile: extra_applications instead of applications (#203)

* extra_applications instead of applications

* get mix docs working

Author: mweidner037

mix.exs

@@ -22,15 +22,15 @@ defmodule Mongo.Ecto.Mixfile do
   #
   # Type `mix help compile.app` for more information.
   def application do
-    [applications: [:ecto, :mongodb_driver, :logger, :telemetry]]
+    [extra_applications: [:logger]]
   end
 
   defp deps do
     [
       {:credo, "~> 1.5.6", only: [:dev, :test], runtime: false},
       {:dialyxir, "~> 1.1.0", only: :dev, runtime: false},
       {:ecto, "~> 3.12"},
-      {:ex_doc, ">= 0.0.0", only: :dev, runtime: false},
+      {:ex_doc, ">= 0.0.0", only: :docs, runtime: false},
       {:excoveralls, "~> 0.16", only: :test},
       {:mongodb_driver, "~> 1.4"},
       {:telemetry, ">= 0.4.0"}