MAGETWO-42613: [GitHub] Fix Grunt refresh task

- Fixed grunt refresh task

Gruntfile.js

@@ -9,6 +9,7 @@ module.exports = function (grunt) {
 
     var _ = require('underscore'),
         path = require('path'),
+        themes = require('./dev/tools/grunt/configs/themes'),
         configDir = './dev/tools/grunt/configs',
         taskDir = './dev/tools/grunt/tasks';
 
@@ -63,14 +64,18 @@ module.exports = function (grunt) {
         },
 
         /**
-         * Refresh magento frontend & backend.
+         * Refresh themes.
          */
-        refresh: [
-            'exec:all',
-            'less:blank',
-            'less:luma',
-            'less:backend'
-        ],
+        refresh: function () {
+            var tasks = [
+                'clean',
+                'exec:all'
+            ];
+            _.each(themes, function(theme, name) {
+                tasks.push('less:' + name);
+            });
+            grunt.task.run(tasks);
+        },
 
         /**
          * Documentation