Add id to migrations table (#2794)

migrations/2021_04_18_040500_change_migrations_add_id_primary_key.php

@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Schema\Builder;
+
+return [
+    'up' => function (Builder $schema) {
+        if (! $schema->hasColumn('migrations', 'id')) {
+            $schema->table('migrations', function (Blueprint $table) {
+                $table->increments('id')->first();
+            });
+        }
+    },
+
+    'down' => function (Builder $schema) {
+        $schema->table('migrations', function (Blueprint $table) {
+            $table->dropColumn('id');
+        });
+    }
+];