Better Controller example for Rails

Take advantage of newer Rails strong params, but also passing strong params in directly like previous example actually messes up the <request> element in response.

We should probably debug and fix that, but don't have capacity at present.

Author: jrochkind

lib/oai/provider.rb

@@ -118,12 +118,16 @@
 # ```ruby
 #   class OaiController < ApplicationController
 #     def index
-#       # Remove controller and action from the options.  Rails adds them automatically.
-#       options = params.delete_if { |k,v| %w{controller action}.include?(k) }
 #       provider = BlogProvider.new
-#       response =  provider.process_request(options)
+#       response =  provider.process_request(oai_params.to_h)
 #       render :body => response, :content_type => 'text/xml'
 #     end
+#
+#     private
+#
+#     def oai_params
+#       params.permit(:verb, :identifier, :metadataPrefix, :set, :from, :until, :resumptionToken)
+#     end
 #   end
 # ```
 #