add-migration init script-migration update-database
dotnet ef migrations add dotnet ef database update
unique constrains on multiple columns modelBuilder.Entity().HasIndex(p => new { p.FirstName, p.LastName }).IsUnique(true);
m-m https://docs.microsoft.com/zh-cn/ef/core/modeling/relationships
page https://www.codingame.com/playgrounds/5363/paging-with-entity-framework-core
how to do Authorization https://github.com/derekgreer/authorize-example/tree/master/src/Examples.Authorization https://stackoverflow.com/questions/31464359/how-do-you-create-a-custom-authorizeattribute-in-asp-net-core
how to add identity to mvc-project https://timmydinheing.com/2018/04/11/adding-asp-net-identity-2-0-into-existing-mvc-project/