New Ghost 2.0 - Custom Editor Cards for Mapping

Just upgraded to Ghost 2.0 yesterday.

Loving the new editor and the concept of adding further editor cards. Do you have an documentation on how how I might go about creating a custom card to fit with the new Ghost 2.0 editor (without of course doing anything to your core code)?

If my custom card works as I would like it to then of course I may release it to the community if it is up to scratch. Custom card idea is to do with mapping but need to see what might be possible before I decide to proceed.

See Can I create a custom code block in Koenig - custom cards aren’t available at this time