Allow event ids from clients

src/usimp/handler/new_event.rs

@@ -26,7 +26,10 @@ async fn new_event(input: Input, session: Option<Session>) -> Result<Output, Err
     let mut uuids = vec![];
     // TODO check permissions
     for mut event in input.events {
-        let uuid = Uuid::new_v4();
+        let uuid = match event.id {
+            Some(id) => id,
+            None => Uuid::new_v4(),
+        };
         event.id = Some(uuid);
         uuids.push(uuid);
         subscription::push_room(&input.room_id, event).await?;