todo/app/Models/Project.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Relations\HasMany;

class Project extends Model
{
    use HasFactory;

    protected $fillable = [
        'id',
        'name',
        'description',
        'department_id',
        'created_by_id',
    ];

    public function department(): BelongsTo
    {
        return $this->belongsTo(Department::class);
    }

    public function users(): BelongsToMany
    {
        return $this->belongsToMany(User::class);
    }

    public function task_statuses(): hasMany
    {
        return $this->hasMany(TaskStatus::class);
    }

    public function tasks(): hasMany
    {
        return $this->hasMany(Task::class);
    }
}