Add possibility to manual add a redemption to a voucher code

[TomDeSmet]

What are you trying to do?
Our client has clients who come to the physical shop with a digital voucher.
When they buy something, our client can manually alter their voucher code's current amount in the CP so her clients are still able to use the amount remaining on the webshop or in the physical shop.
However, there is no history kept for these actions which can be confusing.

What's your proposed solution?
There are of course a few ways to go about this, but the best option would be to be able to manually add redemptions to a voucher with a note field added to it to describe what happened in the physical shop.