proposal: gorm.io/gorm.v1 - Ignore some errors like record not found

[vmlellis]

I wish ignore errors such as "record not found", that is unnecessary to classify as error.

It is the same suggestion to jinzhu/gorm (#805), it's interesting to keep the same option in case the jinzhu/gorm be upgraded to gorm.io/gorm.v1 .

As suggested in the issue of jinzhu/gorm, I also suggest adding an option that can ignore some type of errors like below:

WithErrorFilter(func(err error) bool{
    if errors.Is(err, gorm.ErrRecordNotFound) {
        return false
    }
    return true
})

If you agree about it, I will make a PR.

[knusbaum]

+1 This proposal looks acceptable to me.