rails/rails — pull request #11915 by PavelPenkov (2013-08-16 11:20:07+00:00)
Title: Indifferent access for ActiveModel::Errors hash

I think `full_messages_for` should be consistent with `errors`. Before it was like this

```ruby
class Post
include ActiveModel::Validatations
validates_presence_of :title
end

post = Post.new
post.valid?

post.errors[:title] # => 'can't be blank'
post.errors['title'] # => 'can't be blank'

post.errors.full_messages_for :title # => ['Title can't be blank']
post.errors.full_messages_for 'title' # => []
```