code: function(fields, properties, value, equals)
    {
      function pushIt(model)
      {
        model.$push( fields );
      }
  
      return this.eachWhere( pushIt, properties, value, equals );
    }
docs: Calls {@link Rekord.Model#$push} on models in this collection that meet
  the given where expression.
  
  @method
  @memberof Rekord.ModelCollection#
  @param {String[]} [fields] -
  The set of fields to save for later popping or discarding. If not
  specified, all model fields will be saved.
  @param {whereInput} [properties] -
  See {@link Rekord.createWhere}
  @param {Any} [value] -
  See {@link Rekord.createWhere}
  @param {equalityCallback} [equals=Rekord.equalsStrict] -
  See {@link Rekord.createWhere}
  @return {Rekord.ModelCollection} -
  The reference to this collection.
  @see Rekord.createWhere
  @see Rekord.Model#$push