I still think that some of these objects won't be visible in Bugsnag but
I don't want to test any more on cases that were broken before and may
not be relevant now.
Bugsnag expects a string as value, not an ActiveRecord object. The
result was just "filtered" data, not showing any of the order's
attributes.
Since wanting to share the order data seems a common pattern, I added a
convenience method for it.
At `CapQuantity`'s instantiation time the proxy's order is not yet
initialized, and so `CapQuantity` was checking against nil all the time.
This went unnoticed because the job's specs were not integration-level
tests and were stubbing way too many things.
