use instance_of? instead_of is_a?

lib/generators/simple_controller/simple_controller_generator.rb

@@ -83,13 +83,12 @@ class SimpleControllerGenerator < Rails::Generators::NamedBase
       namespaced_classes.delete_at(1)
       namespaced_class = namespaced_classes.join('::').singularize
       resource_class = namespaced_class.constantize
-      raise NameError if resource_class.is_a? Module
+      raise NameError if resource_class.instance_of? Module
+      resource_class
     rescue NameError
       nil
     end
 
-
-
     # Third priority the camelcased c, i.e. UserGroup
     @resource_class ||= begin
       camelcased_class = controller_class_name.singularize