Added asset_helper file and cache busting token config.

src/application/config/config.php

@@ -262,6 +262,18 @@ $config['log_date_format'] = 'Y-m-d H:i:s';
 */
 $config['cache_path'] = __DIR__ . '/../../storage/cache/';
 
+/*
+|--------------------------------------------------------------------------
+| Cache Busting Token
+|--------------------------------------------------------------------------
+|
+| This token will be appending to asset URLs in order to invalidate the browser
+| cache and enforce end clients to fetch new files. Update the token with each
+| new release.
+|
+*/
+$config['cache_busting_token'] = 'dfsg8s09df8g098';
+
 /*
 |--------------------------------------------------------------------------
 | Encryption Key

src/application/helpers/asset_helper.php

@@ -0,0 +1,29 @@
+<?php defined('BASEPATH') OR exit('No direct script access allowed');
+
+/* ----------------------------------------------------------------------------
+ * Easy!Appointments - Open Source Web Scheduler
+ *
+ * @package     EasyAppointments
+ * @author      A.Tselegidis <alextselegidis@gmail.com>
+ * @copyright   Copyright (c) 2013 - 2017, Alex Tselegidis
+ * @license     http://opensource.org/licenses/GPL-3.0 - GPLv3
+ * @link        http://easyappointments.org
+ * @since       v1.3.0
+ * ---------------------------------------------------------------------------- */
+
+/**
+ * Assets URL helper function.
+ *
+ * This function will create an asset file URL that includes a cache busting parameter in order
+ * to invalidate the browser cache in case of an update.
+ *
+ * @param string $uri Relative URI (just like the one used in the base_url helper).
+ * @param string|null $protocol Valid URI protocol.
+ *
+ * @return string Returns the final asset URL.
+ */
+function asset_url($uri = '', $protocol = NULL) {
+    $ci =& get_instance();
+
+    return base_url($uri . '?' . $ci->config->item('cache_busting_token'), $protocol);
+}