slugs can be so long they break note inserts

[sirilyan]

Sample attempt to insert a slug:

cy-uh-well-nohttpsclassroomsynonymcomhowtobecomeadelegatetothedemocraticnationalconventionhtmlorhttpsbetterutahinstituteorgwhatisadelegatebut-either-way-you-can

Simple fix: chop it down to 128 characters.
Simple fix that won't break again if two slugs collide: chop it down to 120 characters and add a salt