Add documentation
diff --git a/src/passage_app.erl b/src/passage_app.erl
index dc675f9..ba16ef4 100644
--- a/src/passage_app.erl
+++ b/src/passage_app.erl
@@ -1,26 +1,22 @@
-%%%-------------------------------------------------------------------
-%% @doc trace public API
-%% @end
-%%%-------------------------------------------------------------------
-
+%% @copyright 2017 Takeru Ohta <phjgt308@gmail.com>
+%%
+%% @private
-module(passage_app).
-behaviour(application).
-%% Application callbacks
+%%------------------------------------------------------------------------------
+%% 'application' Callback API
+%%------------------------------------------------------------------------------
-export([start/2, stop/1]).
-%%====================================================================
-%% API
-%%====================================================================
-
+%%------------------------------------------------------------------------------
+%% 'application' Callback Functions
+%%------------------------------------------------------------------------------
+%% @private
start(_StartType, _StartArgs) ->
passage_sup:start_link().
-%%--------------------------------------------------------------------
+%% @private
stop(_State) ->
ok.
-
-%%====================================================================
-%% Internal functions
-%%====================================================================
diff --git a/src/passage_sup.erl b/src/passage_sup.erl
index 5cae8f2..92b23d3 100644
--- a/src/passage_sup.erl
+++ b/src/passage_sup.erl
@@ -1,14 +1,32 @@
+%% @copyright 2017 Takeru Ohta <phjgt308@gmail.com>
+%%
+%% @private
-module(passage_sup).
-behaviour(supervisor).
+%%------------------------------------------------------------------------------
+%% Application Internal API
+%%------------------------------------------------------------------------------
-export([start_link/0]).
+%%------------------------------------------------------------------------------
+%% 'supervisor' Callback API
+%%------------------------------------------------------------------------------
-export([init/1]).
+%%------------------------------------------------------------------------------
+%% Application Internal Functions
+%%------------------------------------------------------------------------------
+%% @private
+-spec start_link() -> {ok, pid()} | {error, Reason :: term()}.
start_link() ->
supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+%%------------------------------------------------------------------------------
+%% 'supervisor' Callback Functions
+%%------------------------------------------------------------------------------
+%% @private
init([]) ->
Registry = #{
id => passage_tracer_registry,
