public Startup(IHostingEnvironment env)
{
var builder = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);
builder.AddEnvironmentVariables();
Conf = builder.Build();
DatabaseManager.Instance.SqlConnectionString = Conf.GetConnectionString("DefaultConnection");
databaseName = Conf.GetSection("ConnectionStrings").GetValue <string>("DefaultConnection");
}