Passing error code

bot.go

@@ -84,7 +84,7 @@ func (bot *BotAPI) MakeRequest(endpoint string, params url.Values) (APIResponse,
 		if apiResp.Parameters != nil {
 			parameters = *apiResp.Parameters
 		}
-		return apiResp, Error{apiResp.Description, parameters}
+		return apiResp, Error{Code: apiResp.ErrorCode, Message: apiResp.Description, ResponseParameters: parameters}
 	}
 
 	return apiResp, nil

types.go

@@ -897,6 +897,7 @@ type PreCheckoutQuery struct {
 
 // Error is an error containing extra information returned by the Telegram API.
 type Error struct {
+	Code    int
 	Message string
 	ResponseParameters
 }