I have an Elixir app with two applications inside the lib/ folder:

`myproject/lib/app1
myproject/lib/app2`

They both have files which use Application:

`myproject/lib/app1.exs
myproject/lib/app2.exs`

They each implement `start` and spawn a supervision tree.

In `myproject/mix.exs` I tried:

```
  def application do
    [
      mod: {app1, []},
           {app2, []},
      applications: [:foo, :bar]
    ]
  end

```

But all I get are syntax errors on the line with `{app2, []}`.

Is such a thing even possible? If not, what is the right way to launch separate applications with supervision trees in Elixir?