I am new to Ruby On Rails.
I am facing truble on creating a long running background job.
my target is to send notification to all the active users between two given dates on specific given hour interval.


send notification message after every 8 hours to all active users from March-9, 2016 to June-29, 2016

I already tried this with

gem 'sidekiq', '~> 4.1'

and succefully performed active job. but I am not able to schedule it.
I also tried

gem 'whenever', :require => false

but it creates static crone job which constantly run on spcific time interval. not for dynamic cron job.

is there any way I can do this efficiently.
please help me.