@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        SurveyHasUser that = (SurveyHasUser) o;

        if (id != that.id) return false;
        if (answer != null ? !answer.equals(that.answer) : that.answer != null) return false;

        return true;
    }