rails/rails — pull request #9996 by mikz (2013-03-29 09:15:51+00:00)
Title: Association with inverse_of does not set the parent in association building block

Hi!
I found following issue.

When creating new association object with a block:

```ruby
parent.association.build do |child|
child.parent.equal?(parent) # false
end
```

The block the `child.parent` did not point to the same object.
But when the object is created it points to same instance:

```ruby
child = parent.association.build
child.parent.equal?(parent) # true
```

So this patch fixes it by setting inverse_of record right after object is build for the association.

If the patch is right I'll add CHANGELOG entry and backport it to `3-2-stable` branch.