Create booking transaction in TransactionService
Return Result::Success in success case
Extract payment_process to own method
Move preauthorized braintree payment to transaction service
Move PayPal preauth to transaction service create
Update transactions_api.md
Minimum commission in Money object instead of cents and currency
Merge pull request #735 from sharetribe/transaction-service-booking

Move payment initialization logic to TransactionService.create
Fix broken tests

- No minimum commission, if there is no listing price
Add payment process to transactions table
Take payment_process into use
Default none
Merge pull request #738 from sharetribe/add-payment-process

Add payment process
Refactor and show error on complete preauth failure
Fix ordering of calls and redirects
Fix reference to listing conversation
Fix commission handling with_success call
Fix message saving
Skip saving when no  message
Fix reject link