EntitiesModel.puml

@startuml

class Announcement {
    name: String
    description: String
    price: Decimal
}

class Transaction {
    status: Enum
    when: DateTime
    price: Decimal
}
Transaction "0..1" --up-- "1" Announcement : about >
Transaction "*" --down-- "1" User : seller >
Transaction "*" --down-- "1" User : buyer >
class Admin extends User {}

class Message {
  when: DateTime
  text: String
}
Message "*" --up-- "1" Announcement : for >
Message "*" --down-- "1" User : author >

class User {
  username : String
  password : String
  email : String
  tokens: Decimal
}

class Offer extends Announcement
Offer "*" --right-- "1" User : offerer >

class CounterOffer extends Offer
CounterOffer "*" --up-- "1" Offer : counters >

class ProductOffer extends Offer {}
class ServiceOffer extends Offer {}

class Request extends Announcement
Request "*" --left-- "1" User : requester >

class ProductRequest extends Request {}
class ServiceRequest extends Request {}

class CounterRequest extends Request
CounterRequest "*" --up-- "1" Request : counters >

class Review {
    when: DateTime
    stars: Integer
    message: String
}
Review "*" --up-- "1" User : author >
Review "*" --up-- "1" User : about >


@enduml