Integrating ionic with an existing mobi site

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

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

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

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

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

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