Nil return value on belongs_to association should be handled gracefully
Handle instances of Restforce::SObject, which are hash-like enough to be troublesome
Handle Restforce::Collection when building association models
Better handling of Restforce objects when building associations
Merge pull request #83 from DanOlson/fix-nil-belongs-to

Nil return value on belongs_to association should be handled gracefully
Rails4-style conditional has_many associations