Add `which` to drag helper
Add `which` to drag helper

raelbr/ember-sortable,dianafa/ember-sortable,hilotus/ember-sortable,jgwhite/ember-sortable,dianafa/ember-sortable,raelbr/ember-sortable,jgwhite/ember-sortable,hilotus/ember-sortable,tim-evans/ember-sortable,tim-evans/ember-sortable