public void Seed()
        {
            using (EfDbContext context = new EfDbContext())
            {
                var clients = new List<Client>
                {
                    new Client
                    {
                        FirstName = "Jack",
                        SecondName = "Smith",
                        AccountNumber = "5157543365437123",
                        Balance = 10000
                    },
                    new Client
                    {
                        FirstName = "Anna",
                        SecondName = "Dawson",
                        AccountNumber = "5157845684569855",
                        Balance = 5650
                    },
                    new Client
                    {
                        FirstName = "Tony",
                        SecondName = "Spark",
                        AccountNumber = "5157095600443356",
                        Balance = 15000
                    }
                };

                clients.ForEach(p => context.Clients.Add(p));
                context.SaveChanges();
            }
        }
 public List<Client> GetAllClients()
 {
     using (var context = new EfDbContext())
         {
             if (context.Clients.Count() != 0)
             {
                 return context.Clients.ToList();
             }
             return null;
         }
 }