完善关联的save方法

library/think/model/relation/MorphMany.php

@@ -244,17 +244,30 @@ class MorphMany extends Relation
      * @return Model|false
      */
     public function save($data)
+    {
+        $model = $this->make($data);
+
+        return $model->save($data) ? $model : false;
+    }
+
+    /**
+     * 创建关联对象实例
+     * @param array $data
+     * @return Model
+     */
+    public function make($data = [])
     {
         if ($data instanceof Model) {
             $data = $data->getData();
         }
+
         // 保存关联表数据
         $pk = $this->parent->getPk();
 
-        $model                  = new $this->model;
         $data[$this->morphKey]  = $this->parent->$pk;
         $data[$this->morphType] = $this->type;
-        return $model->save($data) ? $model : false;
+
+        return new $this->model($data);
     }
 
     /**