How to populate array in one-to-many relationship (or may be even persist)?

model User {
  id        String     @id @default(auto()) @map("_id") @db.ObjectId
  email     String     @unique
  articles  Article[]
}

model Article {
  user    User     @relation(fields: [userId], references: [id])
  userId  String   @db.ObjectId
}

findOrCreate(createUserDto: CreateUserDto) {
  return this.prismaService.user.upsert({
    where: { email: createUserDto.email },
    update: {},
    create: {
      email: createUserDto.email,
    }
  });
}

create(createArticleDto: CreateArticleDto) {
  return this.prismaService.article.create({ data: createArticleDto });
}

findOne(id: string) {
 return this.prismaService.user.findUnique({
   where: { id },
   include: {
     articles: true,
   }
 });
}