`add_item` doesn't really make sense, it requires us to understand what this method is doing. what we want to do, is just extract the uri from an object, if it has a uri attribute, or if it's a string, just set it on the card.

make a method called `extract_uri_from_object` and pass it the `card` parameter. It should give back either the `object.uri` or the `object` if it's a string. 

put it in `Balanced::Utils::`