code: func (q *Query) SortBy(fields ...string) *Query {
  	for i := range fields {
  		if fields[i] == Key {
  			panic("Cannot sort by Key.")
  		}
  		found := false
  		for k := range q.sort {
  			if q.sort[k] == fields[i] {
  				found = true
  				break
  			}
  		}
  		if !found {
  			q.sort = append(q.sort, fields[i])
  		}
  	}
  	return q
  }
docs: // SortBy sorts the results by the given fields name
  // Multiple fields can be used