UI Admin aproape finalizat

UC/backend/src/exceptions/userNotExistingError.js

@@ -0,0 +1,8 @@
+class UserNotExistingError extends Error {
+    constructor(message = 'User not found in the system!') {
+        super(message);
+        this.name = 'UserNotExistingError';
+    }
+}
+
+module.exports = UserNotExistingError