fix stupid json unpacking bug turning indexed array to object

app/Models/Proposal.php

@@ -137,10 +137,10 @@ class Proposal extends BaseModel
                 'proposal_id' => $this->getKey(),
                 'note' => $changeset->note,
                 'row_count' => 0, // Will be set later when we are sure about the row count
-                'columns' => array_filter(array_map(function(Column $c) {
+                'columns' => array_values(array_filter(array_map(function(Column $c) {
                     if ($c->toRemove) return null;
                     return $c->toArray(false);
-                }, $columns)),
+                }, $columns))),
             ]);
 
             $newRevision->save(); // this gives it an ID, needed to associate rows

app/Tables/Column.php

@@ -103,12 +103,12 @@ class Column implements JsonSerializable, Arrayable
     public static function columnsFromJson($columns)
     {
         if (is_string($columns)) {
-            $columns = json_decode($columns);
+            $columns = json_decode($columns, true);
         }
 
         return array_map(function ($x) {
             return new Column($x);
-        }, $columns);
+        }, array_values((array)$columns));
     }
 
     /**