code: function (dataset, heatMap, isColumns, sets, setSourceFileName) {
      var promptTool = {};
      var _this = this;
      promptTool.execute = function (options) {
        var metadataName = options.input.dataset_field_name;
        var vector = _this.annotateSets(dataset, isColumns, sets,
          metadataName, setSourceFileName);
  
        heatMap.getProject().trigger('trackChanged', {
          vectors: [vector],
          display: ['text'],
          columns: isColumns
        });
      };
      promptTool.toString = function () {
        return 'Select Fields To Match On';
      };
      promptTool.gui = function () {
        return [
          {
            name: 'dataset_field_name',
            options: morpheus.MetadataUtil.getMetadataNames(
              isColumns ? dataset.getColumnMetadata() : dataset.getRowMetadata()),
            type: 'select',
            value: 'id',
            required: true
          }];
  
      };
      morpheus.HeatMap.showTool(promptTool, heatMap);
  
    }
docs: prompt for metadata field name in dataset