fix: use callback instead of struct for params

README.md

@@ -184,7 +184,7 @@ The provider supports the following databases:
 
 * **Foreign key constraints not generated correctly** -
   If a [Customize JoinTable](https://gorm.io/docs/many_to_many.html#Customize-JoinTable) is defined in the schema, 
-  you need to use the provider as a [Go Program](#as-go-file) and set it up using the `WithJoinTables` option.
+  you need to use the provider as a [Go Program](#as-go-file) and set it up using the `BeforeAutoMigrate` option.
 
   for example if those are your models:
   ```go
@@ -210,9 +210,9 @@ The provider supports the following databases:
   you should use the following code:
   ```go
   stmts, err := gormschema.New("mysql")
-  .WithJoinTables(
-		gormschema.SetupJoinTableParams{Model: &models.Person{}, Field: "Addresses", JoinTable: &models.PersonAddress{}},
-	)
+  .BeforeAutoMigrate( func(db *gorm.DB) {
+		db.SetupJoinTable(&customjointable.Person{}, "Addresses", &customjointable.PersonAddress{})
+	})
   .Load(&models.Person{}, &models.Address{})
   ```
 

gormschema/gorm.go

@@ -27,9 +27,9 @@ func New(dialect string, opts ...Option) *Loader {
 type (
 	// Loader is a Loader for gorm schema.
 	Loader struct {
-		dialect            string
-		config             *gorm.Config
-		joinTableCallbacks []func(*gorm.DB)
+		dialect           string
+		config            *gorm.Config
+		beforeAutoMigrate func(*gorm.DB)
 	}
 	// Option configures the Loader.
 	Option func(*Loader)
@@ -86,8 +86,8 @@ func (l *Loader) Load(models ...any) (string, error) {
 		db.Config.DisableForeignKeyConstraintWhenMigrating = true
 	}
 
-	for _, setupJoinTable := range l.joinTableCallbacks {
-		setupJoinTable(db)
+	if l.beforeAutoMigrate != nil {
+		l.beforeAutoMigrate(db)
 	}
 
 	if err = db.AutoMigrate(models...); err != nil {
@@ -167,18 +167,7 @@ func (m *migrator) CreateConstraints(models []any) error {
 	return nil
 }
 
-type SetupJoinTableParams struct {
-	Model     any
-	Field     string
-	JoinTable any
-}
-
-func (l *Loader) WithJoinTables(params ...SetupJoinTableParams) *Loader {
-	for _, p := range params {
-		l.joinTableCallbacks = append(l.joinTableCallbacks, func(db *gorm.DB) {
-			db.SetupJoinTable(p.Model, p.Field, p.JoinTable)
-		})
-	}
-
+func (l *Loader) BeforeAutoMigrate(cb func(*gorm.DB)) *Loader {
+	l.beforeAutoMigrate = cb
 	return l
 }