Add table column and vertical merging

src/file/table/table-column.ts

@@ -0,0 +1,22 @@
+import { TableCell, VMergeType } from "./table-cell";
+
+export class TableColumn {
+    constructor(private readonly cells: TableCell[]) {}
+
+    public getCell(index: number): TableCell {
+        const cell = this.cells[index];
+
+        if (!cell) {
+            throw Error("Index out of bounds when trying to get cell on column");
+        }
+
+        return cell;
+    }
+
+    public mergeCells(startIndex: number, endIndex: number): TableCell {
+        this.cells[startIndex].addVerticalMerge(VMergeType.RESTART);
+        this.cells[endIndex].addVerticalMerge(VMergeType.CONTINUE);
+
+        return this.cells[startIndex];
+    }
+}