Merge pull request #307 from lrascao/add_bootstrap_usage

bootstrap now accepts --help usage flag

bootstrap

@@ -3,6 +3,14 @@
 %% ex: ft=erlang ts=4 sw=4 et
 
 main(Args) ->
+    case lists:member("--help", Args) of
+        true ->
+            usage(),
+            halt(0);
+        false ->
+            ok
+    end,
+
     %% Get a string repr of build time
     Built = build_time(),
 
@@ -89,6 +97,11 @@ main(Args) ->
               "Place this script anywhere in your path\n"
               "and you can use rebar to build OTP-compliant apps.\n").
 
+usage() ->
+  io:format("Usage: bootstrap [OPTION]...~n"),
+  io:format("    force=1   unconditional build~n"),
+  io:format("    debug     add debug information~n").
+
 is_otp(OtpInfo, Regex) ->
      case re:run(OtpInfo, Regex, [{capture, none}]) of
           match -> true;