Just add Eloquent::unguard();
in the top of the run method when you do a seed, no need to create an $fillable
array in all the models you have to seed.
Normally this is already specified in the DatabaseSeeder
class. However because you're calling the UsersTableSeeder
directly:
php artisan db:seed --class="UsersTableSeeder"
Eloquent::unguard();
isn't being called and gives the error.