Расширение reminders (#19)

Co-authored-by: gorbenko.pavel <gorbenko.pavel@tansu.kz>
Reviewed-on: http://git.tnsu.kz/gorbenko.pavel/tnsu-approval-route/pulls/19

backend/Tnsu.ApprovalRoute.Api/Program.cs

@@ -52,6 +52,7 @@ builder.Services.AddCors(options =>
         .AllowAnyHeader()
         .AllowAnyMethod());
 });
+builder.Services.AddSingleton(TimeProvider.System);
 builder.Services.AddApprovalRouteInfrastructure(builder.Configuration);
 builder.Services.AddApprovalRouteApplication();
 builder.Services.Configure<RemindersOptions>(builder.Configuration.GetSection("Reminders"));