Add a TODO to make things more explicit.

exercises/07_threads/05_channels/tests/insert.rs

@@ -1,3 +1,5 @@
+// TODO: Set `move_forward` to `true` in `ready` when you think you're done with this exercise.
+//  Feel free to call an instructor to verify your solution!
 use channels::data::TicketDraft;
 use channels::{launch, Command};
 use std::time::Duration;
@@ -24,8 +26,6 @@ fn ready() {
     // since our server doesn't expose any **read** actions.
     // We have no way to know if the inserts are actually happening and if they
     // are happening correctly.
-    // Set `move_forward` to `true` when you think you're done with this exercise.
-    // Feel free to call an instructor to verify your solution!
     let move_forward = false;
 
     assert!(move_forward);