Pass db error to new instance

Fix apply option

Update tests script

Fix omit associations, close go-gorm#4161

Clear scopes before invoke scopes methods

Fix after initialize db callback

Fix apply config

Don't override the from clauses, close go-gorm#4129

Refactor nested preloading associations, close go-gorm#3970

Allow foreign key following the default naming conventions, close go-…

…gorm#3928