[modules] Watch for template changes

`build.watch` option was added

lib/build.js

@@ -58,7 +58,8 @@ const defaults = {
   plugins: [],
   babel: {},
   postcss: [],
-  templates: []
+  templates: [],
+  watch: []
 }
 const defaultsLoaders = [
   {
@@ -512,7 +513,7 @@ function watchPages () {
     r(this.srcDir, 'pages/**/*.vue'),
     r(this.srcDir, 'layouts/*.vue'),
     r(this.srcDir, 'layouts/**/*.vue')
-  ]
+  ].concat(this.options.build.watch)
   const options = Object.assign({}, this.options.watchers.chokidar, {
     ignoreInitial: true
   })
@@ -520,7 +521,7 @@ function watchPages () {
   const refreshFiles = _.debounce(() => {
     co(generateRoutesAndFiles.bind(this))
   }, 200)
-  this.pagesFilesWatcher = chokidar.watch(patterns, options)
+  this.pagesFilesWatcher = chokidar.watch(_.uniq(patterns), options)
   .on('add', refreshFiles)
   .on('unlink', refreshFiles)
 }

lib/module.js

@@ -34,7 +34,6 @@ class Module {
     // Generate unique and human readable dst filename
     const dst = template.fileName ||
       (path.basename(srcPath.dir) + '.' + srcPath.name + '.' + hash(src) + '.' + srcPath.ext)
-
     // Add to templates list
     const templateObj = {
       src,
@@ -42,9 +41,15 @@ class Module {
       options: template.options
     }
     this.options.build.templates.push(templateObj)
+    // Watch template for changes
+    this.addWatch(src)
     return templateObj
   }
 
+  addWatch (pattern) {
+    this.options.build.watch.push(pattern)
+  }
+
   addPlugin (template) {
     const {dst} = this.addTemplate(template)
     // Add to nuxt plugins