Move into subdirectory and add Ruby extension file

.gitignore

@@ -1,2 +1,4 @@
 *.DS_Store
 *.o
+*.bundle
+Makefile

ext/digest/extconf.rb

@@ -0,0 +1,2 @@
+require 'mkmf'
+create_makefile('sha3')

ext/digest/sha3.c

@@ -0,0 +1,9 @@
+#include "ruby.h"
+
+static VALUE mDigest, mSHA3;
+
+void
+Init_sha3() {
+	mDigest = rb_define_module("Digest");
+	mSHA3 = rb_define_module_under(mDigest, "SHA3");
+}