/*

• Server side integration for Venmo API
• Please make sure to define client_id, client_secret and scopes before getting started
• For full list of scopes, please see Venmo API documentation. By default, this class implements the bare
• minimum set of scopes to send money from one user to another.
• 1. Call getAuthURL from app and direct user to that URL in app
• 2. Call exchangeToken and pass query param "code" returned from first request
• 3. On success, store the entire response so that you have access to the access and refresh tokens
• 4. Call getUser or Payment request as needed
• See https://developer.venmo.com for more info
• To Do
• 1. Error Handling - https://developer.venmo.com/docs/errors
• 2. Yii wrapper */