[extra-02] install and configure junit formatter

With this change it's possible to generate test report that can be used
alongside continuous integration routine.

mix.exs

@@ -15,9 +15,6 @@ defmodule Wabanex.MixProject do
     ]
   end
 
-  # Configuration for the OTP application.
-  #
-  # Type `mix help compile.app` for more information.
   def application do
     [
       mod: {Wabanex.Application, []},
@@ -25,13 +22,9 @@ defmodule Wabanex.MixProject do
     ]
   end
 
-  # Specifies which paths to compile per environment.
   defp elixirc_paths(:test), do: ["lib", "test/support"]
   defp elixirc_paths(_), do: ["lib"]
 
-  # Specifies your project dependencies.
-  #
-  # Type `mix help deps` for examples and options.
   defp deps do
     [
       {:phoenix, "~> 1.5.9"},
@@ -49,16 +42,11 @@ defmodule Wabanex.MixProject do
       {:crudry, "~> 2.4.0"},
       {:pg_ranges, "~> 1.1"},
       {:credo, "~> 1.5", only: [:dev, :test], runtime: false},
-      {:dialyxir, "~> 1.1", only: [:dev, :test], runtime: false}
+      {:dialyxir, "~> 1.1", only: [:dev, :test], runtime: false},
+      {:junit_formatter, "~> 3.1", only: [:test]}
     ]
   end
 
-  # Aliases are shortcuts or tasks specific to the current project.
-  # For example, to install project dependencies and perform other setup tasks, run:
-  #
-  #     $ mix setup
-  #
-  # See the documentation for `Mix` for more info on aliases.
   defp aliases do
     [
       setup: ["deps.get", "ecto.setup"],