add all modules, better gradle setup, and elixir for server

plt-server/lib/plt_server.ex

@@ -0,0 +1,18 @@
+defmodule PltServer do
+  @moduledoc """
+  Documentation for `PltServer`.
+  """
+
+  @doc """
+  Hello world.
+
+  ## Examples
+
+      iex> PltServer.hello()
+      :world
+
+  """
+  def hello do
+    :world
+  end
+end