When I run the app, I get the error “stderr: panic: runtime error: invalid memory address or nil pointer dereference”. This error occurs when I use the AutoMigrate function

Here is the simple example:

main.go

package main

import (
    "testproject/controllers"
    "testproject/initializers"

    "github.com/gin-gonic/gin"
)

func init() {
    initializers.LoadEnvVariables()
    initializers.ConnectToDb()
    initializers.SyncDatabase()
}

func main() {
    r := gin.Default()
    r.POST("/signup", controllers.Signup)
    r.Run()
}

userModel.go

package models

import "gorm.io/gorm"

type User struct {
    gorm.Model
    Email    string `gorm:"unique"`
    Password string
}

syncDatabase.go

package initializers

import "testproject/models"

func SyncDatabase() {
    GlobalDB.AutoMigrate(&models.User{})
}

thinking that this error is caused by the database, I created and tried different databases but I always encountered the same issue