Allow for custom version class

This pulls from the current model config (if given) to fetch the appropriate class to look up version history - defaulting to `PaperTrail::Version` when no class is set on a configured model.

Author: codealchemy

lib/rails_admin_history_rollback/config/actions/history_index.rb

@@ -24,7 +24,8 @@ class HistoryIndex < Base
           proc do
             @general = true
             @history = @auditing_adapter && @auditing_adapter.listing_for_model(@abstract_model, params[:query], params[:sort], params[:sort_reverse], params[:all], params[:page]) || []
-            @version = ::PaperTrail::Version.find(params[:version_id]) if params[:version_id] rescue false
+            version_class = @abstract_model.model.paper_trail_options.dig(:versions, :class_name).try(:constantize) || ::PaperTrail::Version
+            @version = version_class.find(params[:version_id]) if params[:version_id] rescue false
 
             if request.get? # SHOW