code: function getColorGroups(colors) {
    var colorGroups = [];
  
    colors.forEach(function (color) {
      if (colorGroups.indexOf(color.group) < 0) {
        colorGroups.push(color.group);
      }
    });
  
    return colorGroups;
  }
docs: Returns an array of unique group names.
  
  @param   {Array} colors
  @returns {Array)