public Action <IApplicationBuilder> Configure(Action <IApplicationBuilder> next) => app =>
        {
            _appLifetime.ApplicationStarted.Register(() =>
            {
                if (!_context.Customers.Any())
                {
                    _context.AddRange(
                        new Customer {
                        FirstName = "Jack", LastName = "Richer", Role = Role.User
                    },
                        new Customer {
                        FirstName = "John", LastName = "Wick", Role = Role.Broker
                    },
                        new Customer {
                        FirstName = "Charls", LastName = "Xavier", Role = Role.Admin
                    });
                }

                if (!_context.Tickets.Any())
                {
                    _context.AddRange(
                        new Ticket {
                        Price = 10, Performance = new Performance {
                            Date = DateTime.Now.AddDays(50), Name = "Metallica"
                        }
                    },
                        new Ticket {
                        Price = 20, Performance = new Performance {
                            Date = DateTime.Now.AddDays(50), Name = "Heavy metall"
                        }
                    },
                        new Ticket {
                        Price = 30, Performance = new Performance {
                            Date = DateTime.Now.AddDays(50), Name = "Opera"
                        }
                    });
                }

                _context.SaveChanges();
            });

            next(app);
        };
        private static void AddCustomers(this TicketContext context)
        {
            context.AddRange(
                new Customer {
                Id = 1, FirstName = "FName1", LastName = "LName1", Role = Role.User
            },
                new Customer {
                Id = 2, FirstName = "FName2", LastName = "LName2", Role = Role.Broker
            },
                new Customer {
                Id = 3, FirstName = "FName3", LastName = "LName3", Role = Role.Admin
            });

            context.SaveChanges();
        }
        private static void AddPerformances(this TicketContext context)
        {
            context.AddRange(
                new Performance {
                Id = 1, Date = DateTime.Now.AddDays(20), Name = "Power Metall Fest"
            },
                new Performance {
                Id = 2, Date = DateTime.Now.AddDays(22), Name = "Elton John"
            },
                new Performance {
                Id = 3, Date = DateTime.Now.AddDays(23), Name = "Folk Metall Fest"
            },
                new Performance {
                Id = 4, Date = DateTime.Now.AddDays(19), Name = "Dark Metall Fest"
            });

            context.SaveChanges();
        }
        private static void AddTickets(this TicketContext context)
        {
            context.AddRange(
                new Ticket {
                Id = 1, Performance = context.Performances.Find(1), Price = 50
            },
                new Ticket {
                Id = 2, Performance = context.Performances.Find(2), Price = 120, Buyer = context.Customers.Find(1)
            },
                new Ticket {
                Id = 3, Performance = context.Performances.Find(2), Price = 220
            },
                new Ticket {
                Id = 4, Performance = context.Performances.Find(3), Price = 130
            },
                new Ticket {
                Id = 5, Performance = context.Performances.Find(2), Price = 60
            });

            context.SaveChanges();
        }