public abstract class BaseModel
    {
        public int Id { get; set; }
        public DateTime CreatedAt { get; set; }
        public DateTime UpdatedAt { get; set; }

        public int Version { get; set; }
        public string Remarks { get; set; }
    }

    public class Comments:BaseModel
    {
        public int MsgId { get; set; }
        public int FromUserId { get; set; }
        public string Content { get; set; }
    }

    public class Messages:BaseModel
    {
        public int FromUserId { get; set; }
        public string Content { get; set; }
    }

    public class Users:BaseModel
    {
        public string Username { get; set; }

        public string Password { get; set; }
    }

    public class CommentViewModel
    {
        
        public string FromUserName { get; set; }
        public string Comment { get; set; }
    }

    public class MessageViewModel
    {
        public int Id { get; set; }
        public int FromUserId { get; set; }

        public string Content { get; set; }
        public IEnumerable<CommentViewModel> Comments { get; set; }
    }

    public class SayViewModel
    {
        public string Username { get; set; }
        public IEnumerable<MessageViewModel> Messages { get; set; }
    }