Update rubykassa.rb [ci skip]
Add docs how to setup Robokassa's URLs [ci skip]
depend on Rails >= 3.2.18
erge branch 'master' of github.com:ZeroOneStudio/rubykassa [ci skip]
update supported Rails versions [ci skip]
Merge branch 'master' into feature/success-fail-callbacks
add default values for success/fail callbacks
update Readme [ci skip]