def add(response)
      if @list.key? response.name
        raise DuplicateResponse, "A response named #{response.name} already exists"
      end
      @list[response.name] = response
    end
def add(response)
      if @list.key? response.name
        raise DuplicateResponse, "A response named #{response.name} already exists"
      end
      @list[response.name] = response
    end
Add a response to the list

 @param [Kanpachi::Response] response The response to add.
 @return [Hash<Kanpachi::Response>] All the added responses.
 @raise DuplicateResponse If a response is being duplicated.
 @api public