Merge and fix migration for participants.data hstore field
Preliminary work on getting paypal integrated
Makes Payment an STI class

We now have ManualPayment and allows for PaypalPayment
WIP
WIP
Adds add_host_paypal_account rake task
WIP: Payment notification
Adds logging for GATEWAY.setup_purchase
Adds PayPal specific information to payment table
Redirect to tournament registration page
Adds PayPal request specs