modified fields

changed gw_id to unsigned integer, and added order_id
removed fields

removed order_id & amount fields.
modified merchant id field

modified merchant id field for direcpay settings.
added new route group.

added new route group with before filter ‘isRechargeable’. with several
routes related to online recharge pages.
added new dependency: rahulmkhj/direcpay
added new method: initiate

added new method to initiate a direcpay transaction.
added new view: select_pg

added new view to list all available payment gateways for selection
before making online payment.
"Buy Now!" button now works.