Initial MVP

Specification

For a customer, take all the transactions in a given week and round them up to the
nearest pound. For example with spending of £4.35, £5.20 and £0.87, the round-up
would be £1.58. This amount should then be transferred into a savings goal, helping the
customer save for future adventures.

Roundup Transactions between 'transactionTimes' and add 'amount' to an accounts given savings goal

curl -X PUT 'http://localhost:8080/api/v1/account/0f626e6b-d357-4a35-8219-c4e62df5f326/round-up/e5ed27ef-6bc5-45fd-adf8-2697c4cad02b?fromDate=2020-07-12T20:17:40.122Z&toDate=2020-07-12T20:19:40.122Z'

See README.md for further info