Integrating ionic with an existing mobi site

1

I’ve just started out using ionic and I wanted to know how possible it is to integrate ionic to an already developed mobi site i.e. I have a site I’ve customized for smartphones. I don’t want to start all over again, I want to take my existing code and customize it with ionic. So lets say I have a side menu on my mobi site like

<nav>
		<ul class="nav">
			<li><a href="#">
				<div class="circle">
					<span class="icon icon-group"></span>
				</div> 
				<span class="text">Browse Products</span>
				</a>
			</li>
</ul>
</nav>

I want to make the above code an ion-side menu something like:

<ion-side-menus>
  <!-- Center content -->
  <ion-side-menu-content ng-controller="ContentController">
  </ion-side-menu-content>

  <!-- Left menu -->
  <ion-side-menu side="left">
  </ion-side-menu>
</ion-side-menus>

Is it possible to integrate my existing code with ionic or do I have to recode again with ionic syntax?