code: function ChartColumn () {
      var columnLinker = function (scope, element, attrs, chartCtrl) {
          var column = attrs.columnValues.split(",");
          column.unshift(attrs.columnId);
          chartCtrl.addColumn(column, attrs.columnType, attrs.columnName, attrs.columnColor);
      };
  
      return {
          "require": "^c3chart",
          "restrict": "E",
          "scope": {},
          "replace": true,
          "link": columnLinker
      };
  }
docs: @ngdoc directive
  @name chartColumn
  @description
  `chart-column` Used to provide data values for the chart as well as the name and some other config options.
  
  Restrict To:
  Element
  
  Parent Element:
  c3chart
  
  @param {String} column-id The id used to uniquely identify the column
  
  @param {String} column-values The values for this column to plot.
  
  @param {String} column-type The type of the column to show: line, spline, bar, step, area, area-spline, area-step, scatter, pie, donut, gauge
  
  {@link http://c3js.org/reference.html#data-type| c3js docs}
  
  @param {String} column-name The name of the column as used to print in the label.
  
  {@link http://c3js.org/reference.html#data-names| c3js docs}
  
  @param {String} column-color The color to use for this column.
  
  {@link http://c3js.org/reference.html#data-names| c3js docs}
  
  @example
  Usage:
  <chart-column column-values="..."/>
  
  Example:
  {@link http://jettro.github.io/c3-angular-directive/#examples}
  
  <chart-column column-id="data 1"
  column-name="Data 1"
  column-color="red"
  column-values="30,200,100,400,150,250"
  column-type="spline"/>