rails/activeform — pull request #7 by kirs (2014-09-17 21:41:39+00:00)
Title: Fixed proc call when form with new record was initialized

As I guess from `FormDefinition#initialize`, `proc` is never set.

In my case, it was always `nil` and for new records, the code evaluated `form.instance_eval(&proc)` where `proc` was nil. That lead to `ArgumentError: wrong number of arguments (0 for 1..3)`.