app/views/challenges/index.js.erb
$(".load-more").remove();
$("ul.list-challenges").append("<%= j render partial: 'challenges' %>");
$(".row").last().after("<%= j render partial: 'shared/load_more', locals: { collection: @challenges } %>");
$('html, body').animate({
scrollTop: $(document).height()-$(window).height()},
1400,
"easeOutQuint"
);