Need to correctly infer if a relationship is optional or not

[tosbourn]

In Rails 5 belongs_to relationships are required by default.

However if you just have;

class Model < ApplicationRecord
  belongs_to :other_model
end

Then RailsAdmin marks this field as optional. This can be addressed in the model by doing;

class Model < ApplicationRecord
  belongs_to :other_model, required: true
end

It would be nice if RailsAdmin took into account the version of Rails when deciding if a relationship is required or not.

[ordinaryzelig]

I think the reason is because the validation is actually getting killed somehow. I subitted an issue: #2785.

[tosbourn]

@ordinaryzelig nice, I will close this issue.