修复seeder错误；删除第三方的think迁移工具，在extend中重新实现；

extend/phinx/Db/Plan/Intent.php

@@ -0,0 +1,55 @@
+<?php
+
+/**
+ * MIT License
+ * For full license information, please view the LICENSE file that was distributed with this source code.
+ */
+
+namespace Phinx\Db\Plan;
+
+use Phinx\Db\Action\Action;
+
+/**
+ * An intent is a collection of actions for many tables
+ */
+class Intent
+{
+    /**
+     * List of actions to be executed
+     *
+     * @var \Phinx\Db\Action\Action[]
+     */
+    protected $actions = [];
+
+    /**
+     * Adds a new action to the collection
+     *
+     * @param \Phinx\Db\Action\Action $action The action to add
+     * @return void
+     */
+    public function addAction(Action $action): void
+    {
+        $this->actions[] = $action;
+    }
+
+    /**
+     * Returns the full list of actions
+     *
+     * @return \Phinx\Db\Action\Action[]
+     */
+    public function getActions(): array
+    {
+        return $this->actions;
+    }
+
+    /**
+     * Merges another Intent object with this one
+     *
+     * @param \Phinx\Db\Plan\Intent $another The other intent to merge in
+     * @return void
+     */
+    public function merge(Intent $another): void
+    {
+        $this->actions = array_merge($this->actions, $another->getActions());
+    }
+}