feat: added ticket history

ticketsystem/models.py

@@ -36,3 +36,16 @@ class Comment(models.Model):
 
     def __str__(self):
         return f"Kommentar von {self.author} zu Ticket #{self.ticket.id}"
+
+
+class TicketHistory(models.Model):
+    ticket = models.ForeignKey("Ticket", on_delete=models.CASCADE, related_name="history")
+    changed_by = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
+    changed_at = models.DateTimeField(auto_now_add=True)
+
+    field = models.CharField(max_length=100)  # z. B. "status" oder "description"
+    old_value = models.TextField(null=True, blank=True)
+    new_value = models.TextField(null=True, blank=True)
+
+    class Meta:
+        ordering = ["-changed_at"]