Add Rakefile which is for rake (make written by ruby)

Author: cosmo0920

Rakefile

@@ -0,0 +1,11 @@
+require 'bundler/gem_tasks'
+require 'rake/testtask'
+
+Rake::TestTask.new(:test) do |test|
+  test.libs << 'test'
+  test.pattern = 'test/**/test_*.rb'
+  test.verbose = true
+  test.warning = false
+end
+
+task :default => :test