Fix Task "pug" not found error in production mode

Fixes #221.
Ref jquery/infrastructure#529.

Gruntfile.js

@@ -200,9 +200,24 @@ module.exports = function(grunt) {
   });
 
   grunt.loadTasks('tasks'); // getWiki, docs tasks
-  require('matchdep')
-    .filterAll(['grunt-*', '!grunt-docs'])
-    .forEach(grunt.loadNpmTasks);
+
+  grunt.loadNpmTasks('grunt-autoprefixer');
+  grunt.loadNpmTasks('grunt-contrib-clean');
+  grunt.loadNpmTasks('grunt-contrib-copy');
+  grunt.loadNpmTasks('grunt-contrib-less');
+  grunt.loadNpmTasks('grunt-contrib-pug');
+  grunt.loadNpmTasks('grunt-contrib-uglify');
+  grunt.loadNpmTasks('grunt-sitemap');
+
+  if (process.env.NODE_ENV !== 'production') {
+    grunt.loadNpmTasks('grunt-concurrent');
+    grunt.loadNpmTasks('grunt-contrib-jshint');
+    grunt.loadNpmTasks('grunt-contrib-watch');
+    grunt.loadNpmTasks('grunt-html');
+    grunt.loadNpmTasks('grunt-nodemon');
+    grunt.loadNpmTasks('grunt-open');
+    grunt.loadNpmTasks('grunt-puglint');
+  }
 
   grunt.registerTask('build', 'Build the site', [
     'copy',

package.json

@@ -31,14 +31,14 @@
     "grunt-contrib-clean": "~1.1.0",
     "grunt-contrib-copy": "~1.0.0",
     "grunt-contrib-less": "~2.0.0",
+    "grunt-contrib-pug": "^2.0.0",
     "grunt-contrib-uglify": "~4.0.0",
     "grunt-docs": "https://github.com/gruntjs/grunt-docs.git#d224f17ae21fe606b5b7eca73155a31f4e341930",
     "grunt-sitemap": "~1.2.1",
     "highlight.js": "~9.12.0",
     "less-plugin-clean-css": "~1.5.1",
     "lodash": "~4.17.10",
     "marked": "https://github.com/vladikoff/marked/tarball/032a72231503b63e15e76b990a914becf664b0d7",
-    "matchdep": "~2.0.0",
     "method-override": "~3.0.0",
     "node-schedule": "~1.3.0",
     "pug": "~2.0.3",
@@ -47,7 +47,6 @@
   "devDependencies": {
     "grunt-concurrent": "~2.3.1",
     "grunt-contrib-jshint": "~1.1.0",
-    "grunt-contrib-pug": "^2.0.0",
     "grunt-contrib-watch": "~1.1.0",
     "grunt-html": "~9.3.0",
     "grunt-nodemon": "~0.4.2",