code: func NewMigrator(c *Connection) Migrator {
  	return Migrator{
  		Connection: c,
  		Migrations: map[string]Migrations{
  			"up":   {},
  			"down": {},
  		},
  	}
  }
docs: // NewMigrator returns a new "blank" migrator. It is recommended
  // to use something like MigrationBox or FileMigrator. A "blank"
  // Migrator should only be used as the basis for a new type of
  // migration system.