Update noteable after a new note is added
Created by: jvanbaarsen
What does this do?
It makes sure that whenever a new note is added to a noteable item, the
updated_at of that item is also updated.
Why is this needed?
At this moment when you post a comment on an issue or add a label to an issue,
the updated_at is not changed. Because of this the filtering for least recently
updated is not really useful (since it only takes in account the original text
from the noteable).