Improve help message

Author: kenjis

src/Installer.php

@@ -81,7 +81,7 @@ public static function showMessage(Event $event = null)
         $io->write('$ cd <codeigniter_project_folder>');
         $io->write('$ php bin/install.php');
         $io->write('<info>Above command will show help message.</info>');
-        $io->write('See https://github.com/kenjis/codeigniter-composer-installer for details');
+        $io->write('See <https://github.com/kenjis/codeigniter-composer-installer> for details');
         $io->write('==================================================');
 
         self::deleteSelf();