Second-Post-Model.swift

extension BaseMappable {
    static var firebaseIdKey : String {
        get {
            return "FirebaseIdKey"
        }
    }
    init?(snapshot: DataSnapshot) {
        guard var json = snapshot.value as? [String: Any] else {
            return nil
        }
        json[Self.firebaseIdKey] = snapshot.key as Any
        
        self.init(JSON: json)
    }
}

class Post: Mappable {
    var postId: String?
    var title: String?
    var content: String?
    var author: String?
    
    func mapping(map: Map) {
        postId <- map[Post.firebaseIdKey]
        title <- map["title"]
        content <- map["content"]
        author <- map["author"]
    }
    required init?(map: Map) { }
}