title: Issue while calling particular method inside button block in shoes4
body: <pre><code>While calling method inside button block in SHoes4 it throws error  undefined local variable or method `get_notes' . But when i call inside action it works fine,
  
  Code:
  
  class ShoesApp
   include Shoes
      url '/', :index
  
      def index
        para 'Say something...'
        flow do
          @note = edit_line
          button 'OK' do
            Note.new(:message =&gt; @note.text).save
            @note.text = ''   
            @@result.replace get_notes    # error      
          end         
        end
        @@result = para get_notes # Works fine
      end
  
      def get_notes
        Note.all.map(&amp;:message).join("\n")
      end
  end
  
  Shoes.app :title =&gt; 'Notes', :width =&gt; 260, :height =&gt; 350 
  </code></pre>