added requests library to requirements
added celery task to send bulk sms
added code for sms sender to admin
added celery tasks to settings
removed print
removed username adn api_key
removed database credentials
created the gopher module for airtime recharges
did app restructuring
Merge branch 'feature/issue-11-intergrate-with-gopher-airtime-API' into feature/issue-15-create-models-for-SendAirtime-and-AirtimeApplication
registered app and deleted commented code