How to add custom css classes in menu widgets(apperance>widgets>custom menu)

Hi , I am Newbie to wordpress , i wanted to add a custom menu to the sidebar from widgets>custom menu option,
My Html Code is:

<div class="sidebar thumbnail">
<h3>Quick Links</h3>
<ul>
<li class="active"><a href="#">Home</a></li>
<li><a href="#">Location</a></li>
<li><a href="#">Food</a></li>
<li><a href="#">Stay</a></li>
</ul>
</div>

Code that i have put it into the sidebar

register_sidebar(
    array(
   'name' => __('Main-Sidebar-2','Bootstrap-Framwork'),
   'id' => 'main-sidebar-2',
   'description' => __('This is main Sidebar-2 content Area',''),
   'class' => 'sidebar thumbnail',
   'before_widget' => '<div class="sidebar thumbnail">',
   'after_widget' => '</div>',
   'before_title' => '<h3>',
   'after_title' => '</h3>'
			));

And the HTML Output that im getting is

<div class="sidebar thumbnail"><h3>Quick Links</h3><div class="menu-test-container">
<ul id="menu-test-1" class="menu">
<li class="menu-item menu-item-type-custom menu-item-object-custom menu-item-4"><a href="#">Home</a></li>
<li class="menu-item menu-item-type-custom menu-item-object-custom menu-item-5"><a href="#">About Us</a></li>
<li class="menu-item menu-item-type-custom menu-item-object-custom menu-item-6"><a href="#">Contact us</a></li>
</ul></div></div>

I have googled so many times and i have tried some nav walker but nothing worked.