scales: {
    x: {
        type : 'time',
        time : {
            round : 'minute',
            unit : 'minute'
        },
    },
    y: {
        stacked: true,
        beginAtZero: true,
    }
}

I want to round off the x values to the closet minute and want the coinciding bars to be stacked. I tried this code but fails to stack the bars