How to add a custom field on query result?

model User {
  id         String    @id @default(dbgenerated("uuid_generate_v4()")) @db.Uuid
  posts      Post[]    @relation("author")
  likes      Post[]    @relation("like")

  @@map("users")
}

model Post {
  id         String    @id @default(dbgenerated("uuid_generate_v4()")) @db.Uuid
  author     User      @relation("author", fields: [author_id], references: [id])
  author_id  String    @db.Uuid
  comments   Comment[]
  likedBy    User[]    @relation("like")

  @@map("posts")
}