Exception: ActionView::Template::Error: uninitialized constant for multi-word model dashboard with irregular inflection

• What were you trying to do?
  Setup admin dashboard for model with multi-word irregular inflection.
  example:
  I have a dashboard class: class MerchantBonusDashboard < Administrate::BaseDashboard
  And inflector:

ActiveSupport::Inflector.inflections(:en) do |inflect|
  inflect.irregular 'merchant_bonus', 'merchant_bonuses'
end

during render of the dashboard I get error:

Rails -- Exception: ActionView::Template::Error: uninitialized constant MerchantBonu
Did you mean?  MerchantBonus

Relevant part of the stack trace:

activesupport (6.1.7.4) lib/active_support/inflector/methods.rb:273:in `const_get'
activesupport (6.1.7.4) lib/active_support/inflector/methods.rb:273:in `constantize'
activesupport (6.1.7.4) lib/active_support/core_ext/string/inflections.rb:74:in `constantize'
administrate (0.19.0) lib/administrate/base_dashboard.rb:25:in `model'
activesupport (6.1.7.4) lib/active_support/core_ext/object/try.rb:15:in `public_send'
activesupport (6.1.7.4) lib/active_support/core_ext/object/try.rb:15:in `try'
administrate (0.19.0) app/helpers/administrate/application_helper.rb:26:in `model_from_resource' 

Looking at lib/administrate/base_dashboard.rb:25:in 'model'
I see this impl:

      def model
        to_s.chomp(DASHBOARD_SUFFIX).classify.constantize
      end

to_s.chomp(DASHBOARD_SUFFIX) =>'MerchantBonus'
.classify => 'MerchantBonu'

Rails ActiveSupport Inflector method classify expects a underscore (snake_case) table name, but here we are giving it a CamelCase model name. classify does incidentally work when the table_name arg is CamelCase and doesn't have an multi-word irregular inflection.

Seems like we should do an underscore operation on the CamelCase model name before classifying. e.g.

      def model
        to_s.chomp(DASHBOARD_SUFFIX).underscore.classify.constantize
      end

I could also define an additional inflector for the CamelCase version inflect.irregular 'MerchantBonus', 'MerchantBonuses'. But that seems more of a hack that the proposed change above.

Happy to submit a PR if this seems like a reasonable fix or maybe I'm misunderstanding some aspect.

• What versions are you running?
  • Rails - (6.1.7.4)
  • administrate - (0.19.0)

Start in lib/administrate/base_dashboard.rb:25 and compare the current model resolution with the reported MerchantBonusDashboard and irregular inflection example. Verify the behavior for a multi-word irregular model and confirm that rendering the dashboard no longer raises the reported uninitialized-constant error.