text: angular.module('pokedexApp')
  .directive('rollOnScroll', function(){
      return {
          restrict : 'A',
          link : function(scope, elem, attrs){
              window.onscroll = function(){
                  var rotation = `translateY(-50%) rotateZ(${window.scrollY / 15}deg)`;
                  elem[0].style.transform = rotation;
              }
          }
      }
  })