undisable the button before , incase  wants to disable again.
chore(docs): updated README to reflect Stripe API changes

closes #2
Merge pull request #4 from stephennancekivell/master

undisable the button before $apply, incase $apply wants to disable again.
Merge pull request #5 from bsiddiqui/update-readme

chore(docs): updated README to reflect Stripe API changes