fix user binding, user logic contract and add account exception

Contracts/BindingModels/UserBindingModel.cs

@@ -13,6 +13,7 @@ namespace Contracts.BindingModels
 		public string SecondName { get; set; } = string.Empty;
 		public string Email { get; set; } = string.Empty;
 		public string PasswordHash { get; set; } = string.Empty;
+		public string? Password { get; set; }
 		public DateTime Birthday { get; set; }
 		public RoleBindingModel Role { get; set; } = null!;
 	}

Contracts/BusinessLogicContracts/IUserLogic.cs

@@ -11,6 +11,8 @@ namespace Contracts.BusinessLogicContracts
 {
 	public interface IUserLogic
 	{
+		UserViewModel Login(UserBindingModel model);
+
 		UserViewModel Create(UserBindingModel model);
 
 		UserViewModel Update(UserBindingModel model);

Contracts/Exceptions/AccountException.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Contracts.Exceptions
+{
+	public class AccountException : Exception
+	{
+		public AccountException()
+		{
+		}
+
+		public AccountException(string message) : base(message)
+		{
+		}
+
+		public AccountException(string message, Exception inner) : base(message, inner)
+		{
+		}
+	}
+}