Update Ghost-UI with grunt init

Closes #3554

- Adds a shell command to update Ghost-UI

Gruntfile.js

@@ -227,6 +227,15 @@ var path           = require('path'),
                         stdout: true
                     }
                 },
+                // #### Update Ghost-UI
+                // Used as part of `grunt init`. See the section on [Building Assets](#building%20assets) for more
+                // information.
+                ghost_ui: {
+                    command: path.resolve(__dirname.replace(' ', '\\ ') + '/node_modules/.bin/bower update ghost-ui'),
+                    options: {
+                        stdout: true
+                    }
+                },
                 // #### Generate coverage report
                 // See the `grunt test-coverage` task in the section on [Testing](#testing) for more information.
                 coverage: {
@@ -836,7 +845,7 @@ var path           = require('path'),
         // `bower` does have some quirks, such as not running as root. If you have problems please try running
         // `grunt init --verbose` to see if there are any errors.
         grunt.registerTask('init', 'Prepare the project for development',
-            ['shell:bower', 'update_submodules', 'default']);
+            ['shell:bower', 'shell:ghost_ui', 'update_submodules', 'default']);
 
         // ### Production assets
         // `grunt prod` - will build the minified assets used in production.