update seeders and factories to support Laravel 8

database/seeders/DatabaseSeeder.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Database\Seeders;
+
+use Illuminate\Database\Seeder;
+
+class DatabaseSeeder extends Seeder
+{
+    /**
+     * Run the database seeds.
+     */
+    public function run()
+    {
+        $this->call(NestSeeder::class);
+        $this->call(EggSeeder::class);
+    }
+}