add example of using tags to ignore a field
add example of using tags to ignore a field

cortex/gorp,losinggeneration/gorp,jmoiron/modl,GeertJohan/gorp,yp-engineering/gorp,go-gorp/gorp,kimxilxyong/gorp,coopernurse/gorp,gabelula/gorp,d-g-laptev/gorp,japettyjohn/modl,evenco/gorp,xiaoenai/gorp,GeertJohan/gorp,rickb777/gorp-old2,evenco/gorp,kevinc0825/gorm,japettyjohn/modl,coopernurse/gorp,outdoorsy/gorp,go-gorp/gorp,cortex/gorp,yp-engineering/gorp,mousesun/gorp,outdoorsy/gorp,kevinc0825/gorm,gabelula/gorp,kimxilxyong/gorp,d-g-laptev/gorp,losinggeneration/gorp,mousesun/gorp,rickb777/gorp-old2,xiaoenai/gorp,jmoiron/modl