sqlfixture.go
func FromJSON(db *sql.DB, jsonIn []byte) (Fixture, error) {
	var tables Tables
	err := json.Unmarshal(jsonIn, &tables)
	return New(db, tables), err
}
func FromJSON(db *sql.DB, jsonIn []byte) (Fixture, error) {
	var tables Tables
	err := json.Unmarshal(jsonIn, &tables)
	return New(db, tables), err
}
// FromJSON allows a fixture to be created from json input