Add in the ability to create payments for a given loan using a JSON API call.
You should store the payment date and amount.
Expose the outstanding balance for a given loan in the JSON vended for LoansController#show and LoansController#index.
The outstanding balance should be calculated as the `funded_amount` minus all of the payment amounts.
A payment should not be able to be created that exceeds the outstanding balance of a loan.
You should return validation errors if a payment can not be created.
Expose endpoints for seeing all payments for a given loan as well as seeing an individual payment.
`LoansController#show`
ex: localhost:3000/loans/1
* Shows all the payments associated with the loan
* Shows remaining balance for loan
`LoansController#index`
ex: localhost:3000/loans/
* Shows all loans and their remaining balance
`PaymentsController#show`
ex: localhost:3000/payments/2
* Shows data associated with this payment (ie, payment date & amount)
'PaymentsController#create'
ex: localhost:3000/payments
*validates for incoming data
*persists data if everything is fine
-make sure there is server side and front end validation for payment amount input
-calculate remaining balance every time (perferably serverside) to display on front end.
Payment Schema:
amount:decimal
payment_date: date
loan:Loan
Loan Schema:
funded_amount:decimal
payments:Payment
balance: decimal