Наследование ISaleStorage

This reverts commit 9045e90326.

SquirrelContract/SquirrelDatabase/Implementations/SaleStorageContract.cs

@@ -2,11 +2,12 @@
 using Microsoft.EntityFrameworkCore;
 using SquirrelContract.DataModels;
 using SquirrelContract.Exceptions;
+using SquirrelContract.StoragesContracts;
 using SquirrelDatabase.Models;
 
 namespace SquirrelDatabase.Implementations;
 
-public class SaleStorageContract
+public class SaleStorageContract : ISaleStorageContract
 {
     private readonly SquirrelDbContext _dbContext;
     private readonly Mapper _mapper;