Added "code sharing" to additional ideas

feedback.md

@@ -59,6 +59,7 @@ Should we consider more / less / same number of problems?
 * make it more competitive +2
 * 2-phase work mode: first competitive, then cooperative  
 * Secret test set for unified scoring and performance tests between the groups’ solutions +1
+* Code sharing through commen gitlab repository (in order to support learning by imitation of novices)
 
 **Additional notes**