Refactoring: Added interfaces, custom exceptions, UserManager unit tests, dependency injection/inversion; Regex match search by date, keywords

StudentHouseDashboard/Tests/AnnouncementManagerTest.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tests
+{
+    [TestClass]
+    public class AnnouncementManagerTest
+    {
+
+    }
+}