def call(env)
      result = @app.call(env)

      if result.first == 404 &&
          env['REQUEST_METHOD'] == 'GET' &&
          env['PATH_INFO'] == logout_path(env)
        ::Rack::Response.new('You have been logged out.', 200).finish
      else
        result
      end
    end
def call(env)
      result = @app.call(env)

      if result.first == 404 &&
          env['REQUEST_METHOD'] == 'GET' &&
          env['PATH_INFO'] == logout_path(env)
        ::Rack::Response.new('You have been logged out.', 200).finish
      else
        result
      end
    end
Instantiates the middleware.

 @param app [Rack app] the Rack application on which this middleware
                       should be layered

 When the path is the configured logout path, renders a logout
 response.

 @param env [Hash] a Rack environment