Close the application on back button of android phones

I'm developing a app using angularjs and ionic framework. It has a logout option also. When i logout from my app it goes straight to the home page.But if i press the back button it'll go to page that can be accessed only if you are logged in. How can i create a option to close the app if you press the back button from the home page? I use angularjs.

I used this way but did not work

document.addEventListener("backbutton", function(e){
    if($.mobile.activePage.is('/templates/playlists')){
        /* 
         Event preventDefault/stopPropagation not required as adding backbutton
          listener itself override the default behaviour. Refer below PhoneGap link.
        */
        //e.preventDefault();
        navigator.app.exitApp();
    }
    else {
        navigator.app.backHistory()
    }
}, false);