Create the directory in Config::save if it doesn't exists.

classes/config.php

@@ -161,6 +161,11 @@ public static function save($file, $config)
 		$path or $path = APPPATH.'config'.DS.$file.'.php';
 
 		$path = pathinfo($path);
+
+		if ( ! is_dir($path['dirname']))
+		{
+			mkdir($path['dirname'], 0777, true);
+		}
 
 		return \File::update($path['dirname'], $path['basename'], $content);
 	}