pinterest like grid using ember

I am trying to create pinterest like grid for my web app. I guess on mobile devices it should show two columns and more on large devices.

I have tried using ember-collection but for that i need to know the height of the cards(i need to show cards in the grid) which is not possible for me. I tried using bootstrap after that. Below is my code with bootstrap but it is rendering single column only

<div class="row">
  
     
    
 </div>

Could you please let me know where i am doing mistake?