// Get feed ids by tags.
func getFeedIdsByTags(session *xorm.Session, tags []string) (fids []int64, err error) {
var t []*Tag
err = session.Cols("Fid").In("Name", tags).Find(&t)
if err != nil {
return
}
for _, i := range t {
fids = append(fids, i.Fid)
}
return
}