Patch CanCan deprecated keyword arguments

Solves an issue with use of deprecated positional args. The version of CanCan which fixes this is not currently compatible with OFN...

config/initializers/cancancan.rb

@@ -0,0 +1,12 @@
+module CanCanUnauthorizedMessage
+  # Fix deprecated syntax calling I18n#translate (using keyword args) without using **
+  def unauthorized_message(action, subject)
+    keys = unauthorized_message_keys(action, subject)
+    variables = {:action => action.to_s}
+    variables[:subject] = (subject.class == Class ? subject : subject.class).to_s.underscore.humanize.downcase
+    message = I18n.translate(nil, **variables.merge(:scope => :unauthorized, :default => keys + [""]))
+    message.blank? ? nil : message
+  end
+end
+
+CanCan::Ability.prepend(CanCanUnauthorizedMessage)