var chart = c3.generate({
    data: {
        columns: [
            ['data3', 19, 17, 10, 15, 12, 11],
            ['data1', 11, 15, 14, 13, 17, 17],
            ['data2', 17, 12, 18, 13, 15, 23],
            ['data4', 14, 11, 19, 18, 12, 15]
        ],
        type: 'bar',
        groups: [
            ['data1', 'data3','data2',  'data4']
        ]
    },
    axis: {
      x: {
            type: 'category',
            categories: ['Жуков', 'Сталин', 'Рокоссовский', 'Ерёменко', 'Кожедуб', 'Колобанов']
        }
    },
    grid: {
        y: {
            lines: [{value:0}]
        }
    }
});