Duplicate route named `index` error

My application has links as abc.com which is a homepage and abc.com/user123(has a dynamic segment) which is a user-logged in specific profile page.

Earlier, I achieved this by doing:

this.route('index',{path:'/'}, function (){});
this.route('index', {path:'/:u_name'} , function() {});

Now, after upgrading to 2.10, I am unable to create the required links in my router.js using the above way. It gives rise to the following error in the console:

ember.debug.js:55283 Uncaught Error: You may not add a duplicate route named `index.loading`.

Omitting any one of the two paths does not allow me to achieve the intended result.

What's the new way to accomplish links like abc.com and abc.com/user123?