Laravel:多对多插入

I am getting the error below when I try to insert data in my skill_user which has many to many relationship with users and skills table. User id no 14 exists in users table and skill id no 1 also exists in skills table. The command that I execute is this App\user::find(14)->skill()->save(1);

PHP error: Argument 1 passed to Illuminate\Database\Eloquent\Relations\BelongsToMany::save() must be an instance of Illuminate\Database\Elo quent\Model, integer given, called in C:\xampp\htdocs\tellworld-api\vendor\psy\psysh\src\Psy\ExecutionLoop\Loop.php(90) : eval()'d code on l ine 1 and defined in C:\xampp\htdocs\tellworld-api\vendor\laravel\framework\src\Illuminate\Database\Eloquent\Relations\BelongsToMany.php on line 708

When using a many-to-many relation in Laravel, you should use the attach() function to link models.

So in this case, you can do the following:

App\user::find(14)->skill()->attach(1);