As a user I want to set non-working days for multiple boards at once

Summary

Earlier today I learned that non-working days is registered per board in Jira Agile instead of in one place as it was with Greenhopper (https://answers.atlassian.com/questions/212326/how-does-jira-agile-consider-non-working-days).
We have several boards, and this basically means that I have to register the same X number of non-working days on every board we have in Jira around new years every year.
It would be great to have the possibility to copy these days from one board to another (or perhaps have a general configuration for this that will be adopted for all boards by default), just to remove the work and the possibility of loosing out on one/picking the wrong one, etc.

Workaround

Tested in JIRA Agile 6.7.0
Use the following REST call:

POST http://<jira-baseurl>/rest/greenhopper/1.0/rapidviewconfig/workingdays/nonworkingday/add

With the following JSON data:

{"rapidViewId":2,"iso8601Date":"2015-05-31"}

Where rapidViewId is the ID of the Scrum board, and iso8601Date is date to be added.
Taken from Paul's comment.