With a has_one/belongs_to relationship, what's the best way to guarantee
that the belongs_to object gets created and is accessible alongside the
has_one object? I *think* the after_create callback is a good choice,
but I discovered an oddity while trying it.
ActiveRecord does query caching by default.
If you use build instead of new when creating the child object the
problem is solved, at least for has_many associations. I have no idea
if this works with has_one associations.