Persist the date that was last checked for bdays, so we don't get double congratulations when the bot restarts

DeukBot4/Database/BirthdayHandler.cs

@@ -67,6 +67,14 @@ namespace DeukBot4.Database
                      ((end.Month == start.Month) && (end.Day >= start.Day))) ? 1 : 0);
         }
 
+        public static void Initialize()
+        {
+            var db = Redis.GetDatabase();
+            var dbValue = db.StringGet("lastCheckedBirthday");
+            if (dbValue.HasValue)
+                _lastCheckedDate = DateTime.FromBinary(long.Parse(dbValue));
+        }
+
         private static DateTime _lastCheckedDate;
         // ReSharper disable once FunctionRecursiveOnAllPaths
         public static async Task CheckBirthdays()
@@ -81,6 +89,8 @@ namespace DeukBot4.Database
                 if (today != _lastCheckedDate)
                 {
                     _lastCheckedDate = today;
+                    var db = Redis.GetDatabase();
+                    db.StringSet("lastCheckedBirthday", _lastCheckedDate.ToBinary().ToString("D"));
                     await ActualBirthdayCheck(today);
                 }
             }

DeukBot4/Program.cs

@@ -27,6 +27,7 @@ namespace DeukBot4
         private static async Task SetupScheduler()
         {
             ReminderHandler.Main.CheckReminders();
+            BirthdayHandler.Initialize();
             BirthdayHandler.CheckBirthdays();
         }