code: function getMaxShades(colors) {
    var max = 0;
    var colorGroups = getColorGroups(colors);
  
    colorGroups.forEach(function (colorGroup, colorGroupIndex) {
      // Gets colors that belong to group.
      var groupColors = colors.filter(function (o) {
        return o.group === colorGroup;
      });
  
      var len = groupColors.length;
  
      if (len > max) {
        max = len;
      }
    });
  
    return max;
  }
docs: Returns maximum number of shades.
  
  @param   {Array} colors
  @returns {Number}