add_accepted_channel_of_delivery_code.md

Add a channel of delivery code to the "accepted" list

From time to time, usually following the assurance of a reporting period, DSIT will take the view that an additional IATI "channel of delivery" code should be added to RODA's list of accepted codes. The process for doing this is:

• verify that the candidate code exists in the list of valid "channel of delivery" codes

• add the new "accepted" code to the list of accepted codes

• tweak the spec/helpers/codelist_helper_spec.rb to reflect the new quantity of accepted codes

• note the detail of the additional code in the ./CHANGELOG.md

Refer to commit 6189f90502e20aa9c8200e2b60b8b68e47cf1e40 for an example.