public static async Task<Activity> GetActivityAsync(this IContext db, int jobId)
		{
			var item = await db.Activity.FindAsync(jobId);
			if(item == null)
			{
				item = new Activity() { JobId = jobId };
				db.Activity.Add(item);
				await db.SaveChangesAsync();
			}
			return item;
		}
		public static Activity GetActivity(this IContext db, int jobId)
		{
			var item = db.Activity.Find(jobId);
			if(item == null)
			{
				item = new Activity() { JobId = jobId };
				db.Activity.Add(item);
				db.SaveChanges();
			}
			return item;
		}