def update_todo(todo)
      put_params = {
        :body => todo.put_json,
        :headers => Logan::Client.headers.merge({'Content-Type' => 'application/json'})
      }

      response = Logan::Client.put "/projects/#{@project_id}/todos/#{todo.id}.json", put_params
      Logan::Todo.new response
    end
def update_todo(todo)
      put_params = {
        :body => todo.put_json,
        :headers => Logan::Client.headers.merge({'Content-Type' => 'application/json'})
      }

      response = Logan::Client.put "/projects/#{@project_id}/todos/#{todo.id}.json", put_params
      Logan::Todo.new response
    end
update a todo in this todo list via the Basecamp API

 @param [Logan::Todo] todo the todo instance to update in this todo list
 @return [Logan::Todo] the updated todo instance returned from the Basecamp API