I am trying to use the Mailchimp API 3.0 to insert a user into a list > group > group name with php.
I found a nice example using curl, here it is, but, as you can see, here he shows only to add a user into a list, and not in group > group name.
The problem is that I can't find documentation about adding or deleting a user from groups.
I've tried to add the group into the json data array with label 'interests' and also to add it in the $merge_fields array ( I think this is for v2.0 ), but without success.