Added ticket edit functionality

As said, also minor change to database for testing purposes

backend/src/models.rs

@@ -42,3 +42,8 @@ pub struct TicketCreateScheme {
     pub description: String,
     pub room: i16,
 }
+
+#[derive(Deserialize, Serialize, Debug)]
+pub struct TicketUpdateScheme {
+    pub status: String,
+}