Assign internal request subclass to a constant

[janko]

For named auth classes, internal request subclass is still anonymous:

class RodauthMain < Rodauth::Auth
end

class RodauthApp < Roda
  plugin :rodauth, auth_class: RodauthMain do
    enable :internal_request
  end
end

RodauthMain.internal_request_eval do
  self.class #=> #<Class:0x0000000143b57680>
end

I thought it would be nice for introspection and error messages if the internal subclass was assigned into a constant for named auth classes. With the changes in this pull request, we now have:

RodauthMain.internal_request_eval do
  self.class #=> RodauthMain::InternalRequest
end

This is especially useful with rodauth-rails, which exposes an instance class method that returns an internal request instance:

rodauth = RodauthMain.instance
rodauth #=> #<RodauthMain::InternalRequest ...>

We make the constant private to ensure it stays internal.

[jeremyevans]

This seems fine. I've merged it locally. I'm going to always set the constant, since there is no problem setting the constant even if the auth class is anonymous.