title: Mix task "release" not found error
body: <p>I was setting up an Ubuntu 16.04 server for my Elixir/Phoenix application with edeliver when edeliver failed with the error message <code>** (Mix) The task "release" could not be found</code> along with a exit code of 1. If I go to my build server, git pull my app and run <code>MIX_ENV=prod mix release</code> or just <code>mix release</code> after getting dependencies, I get the same error.</p>
  
  <p>However, the same application works without any problem locally. </p>
  
  <p>My erlang version is <code>erts-9.0</code> and elixir version is <code>1.5.5</code> on both the  server and my local computer. Hex version is also the same at <code>0.16.1</code>.</p>
  
  <p>Phoenix was installed using this command: <code>mix archive.install https://github.com/phoenixframework/archives/raw/master/phx_new.ez</code>.</p>
  
  <p>This is my <code>mix.exs</code> file. </p>
  
  <pre><code>defmodule MyApp.Mixfile do
    use Mix.Project
  
    def project do
      [
        app: :MyApp,
        version: "0.0.1",
        elixir: "~&gt; 1.4",
        elixirc_paths: elixirc_paths(Mix.env),
        compilers: [:phoenix, :gettext] ++ Mix.compilers,
        start_permanent: Mix.env == :prod,
        aliases: aliases(),
        deps: deps()
      ]
    end
  
    # Configuration for the OTP application.
    #
    # Type `mix help compile.app` for more information.
    def application do
      [
        mod: {MyApp.Application, []},
        extra_applications: [:comeonin, :logger, :runtime_tools, :earmark, :distillery, :edeliver]
      ]
    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, "~&gt; 1.3.0"},
        {:phoenix_pubsub, "~&gt; 1.0"},
        {:phoenix_ecto, "~&gt; 3.2"},
        {:mariaex, "&gt;= 0.0.0"},
        {:phoenix_html, "~&gt; 2.10"},
        {:comeonin, "~&gt; 4.0"},
        {:phoenix_live_reload, "~&gt; 1.0", only: :dev},
        {:gettext, "~&gt; 0.11"},
        {:earmark, "~&gt; 1.2.3"},
        {:cowboy, "~&gt; 1.0"},
        {:edeliver, "~&gt; 1.4.4"},
        {:distillery, "~&gt; 1.5.1"}
      ]
    end
  
    # Aliases are shortcuts or tasks specific to the current project.
    # For example, to create, migrate and run the seeds file at once:
    #
    #     $ mix ecto.setup
    #
    # See the documentation for `Mix` for more info on aliases.
    defp aliases do
      [
        "ecto.setup": ["ecto.create", "ecto.migrate", "run priv/repo/seeds.exs"],
        "ecto.reset": ["ecto.drop", "ecto.setup"],
        "test": ["ecto.create --quiet", "ecto.migrate", "test"]
      ]
    end
  end
  </code></pre>
  
  <p>My edeliver configuration file <code>.deliver/config</code> is as follows:</p>
  
  <pre><code>APP="MyApp"
  
  BUILD_HOST="1.1.1.1"
  BUILD_USER="ubuntu"
  BUILD_AT="/home/ubuntu/app_build"
  
  PRODUCTION_HOSTS="1.1.1.1" 
  PRODUCTION_USER="ubuntu" 
  DELIVER_TO="/home/ubuntu/app_release" 
  
  pre_erlang_get_and_update_deps() {
    local _prod_secret_path="/home/ubuntu/app_config/prod.secret.exs"
    if [ "$TARGET_MIX_ENV" = "prod" ]; then
      __sync_remote "
        ln -sfn '$_prod_secret_path' '$BUILD_AT/config/prod.secret.exs'
      "
    fi
  }
  </code></pre>