Resources/standard-edition/src/js/admin/PostModel.js
function() {
        return _.map(ko.unwrap(that.relations), function(relation) {
          return ko.unwrap(relation.relatedPost.id);
        });
      }
function() {
        return _.map(ko.unwrap(that.relations), function(relation) {
          return ko.unwrap(relation.relatedPost.id);
        });
      }
returns the index value of the entities connected to the entity