add typescript:upgrade task

Author: gfx

Rakefile

@@ -1,2 +1,12 @@
 #!/usr/bin/env rake
-require "bundler/gem_tasks"
+require 'bundler/gem_tasks'
+
+desc 'download the latest TypeScript source files'
+task 'typescript:download' do
+  sh 'npm', 'install', '-g', 'typescript'
+end
+
+desc 'upgrade TypeScript source files'
+task 'typescript:upgrade' => %i(typescript:download) do
+  mv 'node_modules/typescript', 'lib/support'
+end