RIDGEFIELD — A Union Ridge Elementary School librarian is using an interesting tactic to promote good behavior: ninjas. Librarian Jubilee Roth created a “library ninja program” that includes a set of rules encouraging proper library etiquette by students. “They follow all library routines in a sneaky, stealthy, leave-no-trace book shopping way,” she said. Rules include: Ninjas use their bookshelf markers correctly; ninjas use their whisper voices; ninjas clean up after themselves and others; and ninjas read. One becomes a “master ninja librarian” when they’ve routinely followed the rules, earning a ninja headband handmade by Roth and a selfie with her posted on the wall.