From the publishing tool, publishers will be able to add an arbitrary number of collections and featured applications to a region (country + operator)/page (category + homepage) pair. To do this, we need an endpoint that allows users to remove collections from a region/page pair. This endpoint should be protected by the Apps:Publisher permission created in bug 894425.
Note: this bug is about removing collections from a region/page pair, not adding like comment #0 says (adding is bug 894643). Once bug 903489 is done the only thing left to do here would be to test that you can set region/category/carrier back to the default value, that would effectively unlink the Collection from the corresponding region/category/carrier.
Fixed by changes from bug 903489, I added a test in https://github.com/mozilla/zamboni/commit/90d718d9b568bd7e9d2987a36f175abcf22ea734 to make sure. STR: - Follow steps in bug 903489 for creating and then editing region/category/carrier - Verify using the same steps as well that passing null as the value for all 3 works.