Dev extreme user add using dx data grid

Hi I'm using dx data grid in voyager laravel however When I'm inserting a user its id is auto incremented and userid will fetch from db but I don't know how to fetch userid from db.

$("#gridContainer").dxDataGrid({ dataSource: attendances, showBorders: true, hoverStateEnabled: true, showRowLines:true, rowAlternationEnabled:true, selection: { mode: "multiple" }, "export": { enabled: true, fileName: "Employees", allowExportSelectedData: true }, groupPanel: { visible: false }, paging: { pageSize: 10, enabled: true, }, filterRow: { visible: true },

    grouping: {
        contextMenuEnabled: true,
        expandMode: "rowClick"
    },

    editing: {
        mode: "popup",
        allowAdding: is_editable,
        allowDeleting: is_editable,
        allowUpdating: is_editable,
        popup: {
            title: "Employee Attendance  Information",
            showTitle: true,
            id: "employees->id",
            position: "{ my: 'center",
             showCloseButton: true

        }
    },
    columns: [{
            dataField: 'id',
            allowEditing: false,
            caption: "id",
            width:90,
            id: "attendances->id",

        },{
            dataField: 'user_id',
            allowEditing: false,
            caption: "User_id",
            width:90,


        },
        {
            dataField: "name",
            caption: "Name",
            allowediting: false,

            validationRules: [{ type: "required" },
            {
        type: "pattern",
        pattern: /^[^0-9]+$/,
        message: "Do not use digits in the Name."
    }]
            //  lookup: {
            // dataSource: name

            // }

        }, 
            {
                dataField: 'attendance_month', 
                caption: "Attendance Date",
                dataType: 'date',
                format:  " yyyy-MM-dd, EEEE",
                allowediting: true,
                validationRules: [{ type: "required" }]
              },



         {
            dataField: "attendance_type",
            caption: "Attendance Type",
            allowediting:true,
             validationRules: [{ type: "required" }],
            lookup: {
                dataSource: [

                        "present",
                        "absent",
                        "onleave"
                    ],


            }
        }


    ],

    onRowRemoving: function(item) {

        $.ajax({
            type: 'POST',
            dataType: 'json',
            url: "",
            data: {
                'id': item.data.id,
                '_method': 'delete'
            },
            success: function(data) {}
        });
    },
    onRowUpdating: function(item) {

        url = "";

        $.ajax({
            type: 'post',
            dataType: 'json',
            url: url,
            data: {
                'id': item.key.id,
                'item': item.newData
            },
            success: function(data) {}
        });
    },
    onRowInserting: function(item) {
        $.ajax({
            type: 'post',
            dataType: 'json',
            url: "",
            data: {
                'item': item.data
            },
            success: function(data) {

                window.location.reload();
            }
        });

    },

    onSelectionChanged: function(selectedItems) {
        var url = "";
        var data = selectedItems.selectedRowsData;
        if (data.length > 0) {
            selectedArr = $.map(data, function(value) {
                return value.id;
            });
        } else {
            $('#createButton').attr("target", "_blank");
            $('#createButton').attr("href", "");
        }
    },
    onSelectionChanged: function(selectedItems) {
        var url = "";
        var data = selectedItems.selectedRowsData;
        if (data.length > 0) {
            selectedArr = $.map(data, function(value) {
                return value.id;
            });
        } else {
            $('#createButton').attr("target", "_blank");
            $('#createButton').attr("href", "");
        }
    },

via Chebli Mohamed