add option to upload file when creating a table

app/Models/Row.php

@@ -83,6 +83,7 @@ class Row extends BaseModel
      */
     public static function allocateRowIDs($count)
     {
+        if ($count == 0) return null;
         $last = \DB::selectOne("SELECT multi_nextval('global_row_id_seq', ?) AS last_id;", [$count])->last_id;
         return [$last - $count + 1, $last];
     }