Post.php

<?php
...
class CreatePostsTable extends Migration
{
   
    public function up()
    {
        Schema::create('posts', function (Blueprint $table) {
            $table->increments('id')->unsigned();
            $table->integer('user_id')->unsigned();
            $table->foreign('user_id')->references('id')->on('users')->onUpdate('cascade')->onDelete('cascade');
            $table->string('photo');
            $table->string('description');
            $table->timestamps();
        });
    }
    ...
}