php_laravel_laracasts/app/User.php

<?php

namespace App;

use Illuminate\Notifications\Notifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name', 'email', 'password',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];

    public function posts() {
        return $this->hasMany(Post::class);
    }

    public function publish(Post $post) {
        // Why not $post->save(); ?
        // It would not carry the user information present in the posts() collection.

        $this->posts()->save($post);
    }
}