Search and recent videos

Adding search, recent videos, users, and authentications.
I'm confused - how am I not using shoulda_matchers here? Isn't that what it { should validate_presence_of(:password)} is? I'm following this: http://thoughtbot.github.io/shoulda-matchers/v2.7.0/Shoulda/Matchers/ActiveModel.html#validate_presence_of-instance_method