can :add, Comment, attachable: {user_id: user.id}
can [:update, :delete], Comment, user_id: user.id
authorize! :add, @comment = Comment.new(attachable: @post)
$scope.$watch('[w,h]', function(values){
var w = values[0] || 0, h = values[1] || 0;
$scope.s = w*h;
}, true);
$('#target-element').removeClass('animation');
setTimeout(function(){ $('#target-element').addClass('animation'); }, 0);