Row adding, some webpack tweaks

app/Tables/RowNumerator.php

@@ -5,28 +5,15 @@ namespace App\Tables;
 
 use App\Models\Row;
 
-class RowNumerator
+class RowNumerator extends BaseNumerator
 {
-    /** @var int */
-    private $next;
-    /** @var int */
-    private $last;
-
     /**
      * Create a numerator for the given number of rows.
      *
-     * @param int $capacity
+     * @param int $capacity - how many
      */
     public function __construct($capacity)
     {
-        list($this->next, $this->last) = Row::allocateRowIDs($capacity);
-    }
-
-    public function next()
-    {
-        if ($this->next > $this->last)
-            throw new \OutOfBoundsException("Row numerator has run out of allocated GRID slots");
-
-        return $this->next++;
+        parent::__construct(Row::allocateRowIDs($capacity));
     }
 }