I have just found something very strange.
Let’s imagine that I have posts that belong to an author.
If I do the following (the order doesn’t matter):
apost.author = Author.find(3)
apost.author_id = 2
I get a post that has both an :author_id => 2 attribute, and an
associated Author with id 3.
Then, post.save, and the author_id in the DB is 3.
I think that this is a little bit confusing… Is there something useful
in allowing to have both an author_id and an author that do not match?