You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: v190.go
    path of file: ./repos/gitea/models/migrations/v1_16
    
    the code of the file until where you have to start completion: // Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package v1_16 //nolint

import (
	"fmt"

	"xorm.io/xorm"
)

func A
    
func AddAgitFlowPullRequest(x *xorm.Engine) error {
	type PullRequestFlow int

	type PullRequest struct {
		Flow PullRequestFlow `xorm:"NOT NULL DEFAULT 0"`
	}

	if err := x.Sync(new(PullRequest)); err != nil {
		return fmt.Errorf("sync2: %w", err)
	}
	return nil
}