code: function RelationCollection(database, model, relator, models, remoteData)
  {
    Class.props(this, {
      model:    model,
      relator:  relator
    });
  
    this.init( database, models, remoteData );
  }
docs: An extension of the {@link Rekord.ModelCollection} class for relationships.
  
  @constructor
  @memberof Rekord
  @extends Rekord.ModelCollection
  @param {Rekord.Database} database -
  The database for the models in this collection.
  @param {Rekord.Model} model -
  The model instance all models in this collection are related to.
  @param {Rekord.Relation} relator -
  The relation instance responsible for relating/unrelating models.
  @param {modelInput[]} [models] -
  The initial array of models in this collection.
  @param {Boolean} [remoteData=false] -
  If the models array is from a remote source. Remote sources place the
  model directly into the database while local sources aren't stored in the
  database until they're saved.