Option to enable grouping and add multiple tasks to a row

[iaminamcom]

I was in need to add group so that I can add tasks to specify rows. I found #95 is still open and solutions there are working but not compatible with new version.
Here's an implementation which allow user to enable or disable grouping also fixes rows, lines issues.

What changed

You need to add following to options

new Gantt('.gantt-target', tasks, {
    enable_grouping:  true,
    // Other options...
});

and in tasks will be like

let tasks = [
    {
        start: '2024-03-30',
        duration: '12h',
        name: 'Write new content',
        id: 'Task 1',
        progress: 5,
        // important: true,
        group: 0,
    },
    {
        start: '2024-04-01',
        end: '2024-04-01',
        name: 'Redesign website',
        id: 'Task 0',
        progress: 30,
        group: 0,
    },
    {
        start: '2024-04-02',
        end: '2024-04-02',
        name: 'Apply new styles',
        id: 'Task 2',
        progress: 80,
        group: 0,
    },
    {
        start: '2024-04-04',
        end: '2024-04-04',
        name: 'Review',
        id: 'Task 3',
        progress: 5,
        group: 1,
    },
    {
        start: '2024-04-06',
        end: '2024-04-06',
        name: 'Deploy',
        id: 'Task 4',
        progress: 0,
        group: 1,
    },
];