'DbContextOptionsBuilder' does not contain a definition for 'UseSqlServer' and no accessible extension method 'UseSqlServer' accepting a first argument of type 'DbContextOptionsBuilder' could be found (are you missing a using directive or an assembly reference?)

var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");

        builder.Services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(connectionString));