app\models\Beatmapset::nominate PHP Method

    public function nominate(User $user)
    {
        if (!$this->isPending()) {
            return false;
        }
        DB::transaction(function () use($user) {
            $nomination = $this->recentEvents()->nominations()->where('user_id', $user->user_id);
            if (!$nomination->exists()) {
                $this->events()->create(['type' => BeatmapsetEvent::NOMINATE, 'user_id' => $user->user_id]);
                if ($this->currentNominationCount() >= $this->requiredNominationCount()) {
                    $this->qualify();
                }
            }
        });
        return true;
    }