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);
        });
      }
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
returns the index value of the entities connected to the entity