ruby date scope not working on heroku -

ruby date scope not working on heroku -

i have date scope set in model presents guide info if within current date range. example:

a guide entry set between 10th of june , 18th of july, hence code should activate scope.

scope :active_at_date, lambda { where("date_starting < :date , date_ending > :date", date: date.today )}

it seems working fine locally. on heroku not.

why? , how can prepare works on heroku?

thanks in advance.

ruby-on-rails ruby heroku time