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

StudentHouseDashboard/Logic/Exceptions/DatabaseOperationException.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Logic.Exceptions
+{
+    public class DatabaseOperationException : ApplicationException
+    {
+        public DatabaseOperationException(string? message) : base(message)
+        {
+        }
+
+        public DatabaseOperationException(string? message, Exception? innerException) : base(message, innerException)
+        {
+        }
+    }
+}