Clean up the Rakefile

Rakefile

@@ -1,9 +1,9 @@
 #!/usr/bin/env rake
 
-require 'bundler'
-Bundler::GemHelper.install_tasks
-
+require 'bundler/gem_tasks'
 require 'rake/testtask'
+require 'yard'
+
 Rake::TestTask.new do |test|
   test.libs << 'lib' << 'test'
   test.pattern = 'test/**/*_test.rb'
@@ -13,12 +13,8 @@ end
 task :default => :test
 
 namespace :doc do
-  require 'yard'
   YARD::Rake::YardocTask.new do |task|
-    task.files   = ['README.md', 'LICENSE.md', 'lib/**/*.rb']
-    task.options = [
-      '--output-dir', 'doc/yard',
-      '--markup', 'markdown',
-    ]
+    task.files = %w(README.md lib/**/*.rb)
+    task.options = %w(--output-dir doc/yard --markup markdown)
   end
 end