I have an Active Record model that contains attributes: expiry_date. How do I go about validating it such that it is after today(present date at that time)? I am totally new to
Your question is (almost) exactly answered in the Rails guides.
Here's the example code they give. This class validates that the date is in the past, while your question is how to validate that the date is in the future, but adapting it should be pretty easy:
class Invoice < ActiveRecord::Base
validate :expiration_date_cannot_be_in_the_past
def expiration_date_cannot_be_in_the_past
if expiration_date.present? && expiration_date < Date.today
errors.add(:expiration_date, "can't be in the past")
end
end
end