Create subtransactions in YNAB for Venmo deposits

[golf1052]

Before

After (with categories filled in)

YNAB API documentation and endpoints.

• Users must be able to authenticate with YNAB similar to how they authenticate with Venmo
• Users must set a default budget in YNAB
• Users must be able to set a default account in Slack
  • Upon authentication prompt users to select a default account
• The server must query YNAB every hour to check for new Venmo deposits in the user's default budget under their selected account
• The server must find all payments to the Venmo user between their last two deposits and create subtransactions for each Venmo payment in ascending order.
  • Ascending order is used because money sent to the user closer to the deposit is more likely to be in the Venmo account.
• If multiple Venmo deposits are found one after another in YNAB a new transaction in YNAB must be made with the combined amount of those deposits and the subtransactions must go under that new transaction.
  • The old transactions should have their memo updated to say something like "<DELETE ME: Combined into $X Transfer from Venmo>"
• If the amount of money for a deposit is greater than the amount of Venmo payments between deposits the remaining amount must have a memo of "UNKNOWN"
• If the amount of money for a deposit is less than the amount of Venmo payments between deposits the remaining Venmo payments are ignored.
• In Slack, users should be able to create a mapping between a Venmo note and a YNAB category name so that the server can automatically categorize subtransactions.

Commands

/venmo ynab - Prompt the user for authorization if they are not authorized. Show Venmo YNAB commands if they are authorized
/venmo ynab code [code] - Completes YNAB authorization
/venmo ynab help - Show Venmo YNAB commands
/venmo ynab list account[s] - List YNAB accounts under the default budget
/venmo ynab set account [number] - Set the default YNAB account to use
/venmo ynab list categories - List all YNAB categories
/venmo ynab list mapping - List all Venmo to YNAB mappings
/venmo ynab set mapping "[note]" to "[YNAB category]" - Create/update a mapping from a Venmo note to a YNAB category
/venmo ynab delete mapping [number] - Delete a mapping