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: 1691702379_updated_devices.go
    path of file: ./repos/UpSnap/backend/migrations
    
    the code of the file until where you have to start completion: package migrations

import (
	"encoding/json"

	"github.com/pocketbase/dbx"
	"github.com/pocketbase/pocketbase/daos"
	m "github.com/pocketbase/pocketbase/migrations"
	"github.com/pocketbase/pocketbase/models/schema"
	"github.com/pocketbase/pocketbase/tools/types"
)

func init() {
	m.Register(func(db dbx.Builder) error {
		dao := daos.New(db);

		collection, err := dao.FindCollectionByNameOrId("z5lghx2r3tm45n1")
		if err != nil {
			return err
		}

		collection.ListRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && id ?= @collection.permissions.read.id")

		collection.ViewRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && id ?= @collection.permissions.read.id")

		collection.CreateRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && @collection.permissions.create = true")

		collection.UpdateRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && id ?= @collection.permissions.update.id")

		collection.DeleteRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && id ?= @collection.permissions.delete.id")

		// add
		new_created_by := &schema.SchemaField{}
		json.Unmarshal([]byte(`{
			"system": false,
			"id": "naciykac",
			"name": "created_by
    
func init() {
	m.Register(func(db dbx.Builder) error {
		dao := daos.New(db);

		collection, err := dao.FindCollectionByNameOrId("z5lghx2r3tm45n1")
		if err != nil {
			return err
		}

		collection.ListRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && id ?= @collection.permissions.read.id")

		collection.ViewRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && id ?= @collection.permissions.read.id")

		collection.CreateRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && @collection.permissions.create = true")

		collection.UpdateRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && id ?= @collection.permissions.update.id")

		collection.DeleteRule = types.Pointer("@request.auth.id = @collection.permissions.user.id && id ?= @collection.permissions.delete.id")

		// add
		new_created_by := &schema.SchemaField{}
		json.Unmarshal([]byte(`{
			"system": false,
			"id": "naciykac",
			"name": "created_by",
			"type": "relation",
			"required": false,
			"unique": false,
			"options": {
				"collectionId": "27do0wbcuyfmbmx",
				"cascadeDelete": false,
				"minSelect": null,
				"maxSelect": 1,
				"displayFields": [
					"username"
				]
			}
		}`), new_created_by)
		collection.Schema.AddField(new_created_by)

		return dao.SaveCollection(collection)
	}, func(db dbx.Builder) error {
		dao := daos.New(db);

		collection, err := dao.FindCollectionByNameOrId("z5lghx2r3tm45n1")
		if err != nil {
			return err
		}

		collection.ListRule = nil

		collection.ViewRule = nil

		collection.CreateRule = nil

		collection.UpdateRule = nil

		collection.DeleteRule = nil

		// remove
		collection.Schema.RemoveField("naciykac")

		return dao.SaveCollection(collection)
	})
}