amatsuda/active_decorator — pull request #22 by joker1007 (2013-05-20 04:43:11+00:00)
Title: Add 'respond_to_missing?' to ActiveDecorator::Helper

When I want to detect a helper method that is defined in a controller,
I must write like following.

```ruby
module SampleDecorator
def invoke_helper_method
ActiveDecorator::ViewContext.current.respond_to?(:helper_method) ? helper_method : nil
end
end
```

this patch enable to write in this way.

```ruby
module SampleDecorator
def invoke_helper_method
respond_to?(:helper_method) ? helper_method : nil
end
end
```