Explicitly set serializer for associations

[ggordon]

Adding back the ability to specify the serializer for an association.
Ex. has_one :author, serializer: PersonSerializer

[joaomdmoura]

Trying to fetch :options from :options don't contribute to readability. But it's okay for me. It's just a detail, I liked the implementation 👍
If you want to try a different approach you could simply add options[:options] content to the type level.

[joaomdmoura]

@ggordon, would be cool to update the README either 😄
LGTM 👍

[ggordon]

@joaomdmoura Thanks for feedback, I'll update the README.

[mieko]

I noticed the implementation doesn't guard against nil associations like the implicit version of the call, that is:

class UserSerializer < ActiveModel::Serializer
  # ...
end

# Assume comment.user == nil
class CommentSerializer < ActiveModel::Serializer
  # This call guards against nil, outputting null, when implicitly using UserSerializer
  belongs_to :user

  # When it's made explicit, if user is nil, a UserSerializer is created anyway, 
  # with the nil object, and errors out trying to access members.
  belongs_to :user, serializer: UserSerializer
end

[ggordon]

@mieko Thanks, I'll look into it.

[kurko]

@ggordon can you rebase? Also, can you find a better name for the options commented? Perhaps association_options?

[ggordon]

@kurko I'll fix and rebase in the morning.

[kurko]

Thanks for your work, @ggordon, and sorry for the huuuuge delay.

[ggordon]

No problem. @kurko, thanks for merging!