associate laravel

$account = App\Account::find(10);

$user->account()->associate($account);

$user->save();When updating a belongsTo relationship, you may use the associate method. This 
method will set the foreign key on the child model:

	$account = App\Account::find(10);
	$user->account()->associate($account);
	$user->save();

When removing a belongsTo relationship, you may use the dissociate method. This
method will set the relationship foreign key to null:

	$user->account()->dissociate();
	$user->save();//id for single
$user->reasons->attach($reasonId);

//array for multiple
$user->reasons->attach($reasonIds);

$user->save();<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Project extends Model
{
    /**
     * Get all of the deployments for the project.
     */
    public function deployments()
    {
        return $this->hasManyThrough(Deployment::class, Environment::class);
    }
}