Create `Todo` entity in database

[miguel5g]

The structure should look like this

model User {
  ...
  todos       Todo[]
  ...
}

model Todo {
  id        String     @id @default(uuid())
  title     String
  status    TodoStatus
  authorId  String     @map("author_id")
  author    User       @relation(fields: [authorId], references: [id])
  createdAt DateTime   @default(now()) @map("created_at")
  updatedAt DateTime   @updatedAt @map("updated_at")

  @@map("todos")
}

enum TodoStatus {
  TODO
  DOING
  DONE
}