Wow. Yeah, you're right... the master branch readme has the below
notice, but not the 3.0 branch, since it's not being maintained any
more. (The 3.0 readme doesn't mention that it's not maintained
either.) Honestly, I'd recommend against using rails_admin unless
you're on master. Even then, you should expect to need to learn the
internals to debug stuff... this is alpha software. (No offense,
maintainers! It's rad, thanks for your work :) )
Anyway, the alternative is a block in an initializer like this:
RailsAdmin.config do |config|
...
end
------
Configuration with ActiveRecord::Base#rails_admin is not recommended
anymore and should be considered as expermimental (development) until
further notice. Unfortunately, implementation of this feature is
thougher than imagined. Any help is welcome, as usual. Please remove
any rails_admin configuration from your ActiveRecord model and put it
inside an initializer (as shown in this documentation now).