JSAdm: Docs for adding products to categories

[nvdid]

First I want to thank you guys for the great project.

Couldn't find a documentation for the purpose and as a newbie here it took me quite some time to find the correct way of doing this:

curl -b cookies.txt -c cookies.txt \
-X PATCH 'http://localhost:8000/default/jsonadm/product/11?_token=...' \
-H 'Content-Type: application/json' \
-d '{"data": {
    "type": "product",
    "relationships": {
        "catalog": {
            "data": [{
                "id": "48",
                "type": "catalog"
            }]
        }
    }
}}'

It adds product 11 to category 48. Not sure but I think it can go under manage resources

[aimeos]

Thanks! It's already described in the "Create items" section but maybe it's good idea to add that to the "Update items" section too. Can you please create a pull request, please?

[nvdid]

I did:)
#55