added the storage_path constant.

application/config/error.php

@@ -49,7 +49,7 @@ return array(
 
 	'logger' => function($severity, $message)
 	{
-		System\File::append(APP_PATH.'storage/log.txt', date('Y-m-d H:i:s').' '.$severity.' - '.$message.PHP_EOL);
+		System\File::append(STORAGE_PATH.'log.txt', date('Y-m-d H:i:s').' '.$severity.' - '.$message.PHP_EOL);
 	},
 
 );

public/index.php

@@ -27,6 +27,7 @@ define('MODEL_PATH', APP_PATH.'models/');
 define('PACKAGE_PATH', APP_PATH.'packages/');
 define('ROUTE_PATH', APP_PATH.'routes/');
 define('SESSION_PATH', APP_PATH.'storage/sessions/');
+define('STORAGE_PATH', APP_PATH.'storage/');
 define('SYS_VIEW_PATH', SYS_PATH.'views/');
 define('VIEW_PATH', APP_PATH.'views/');