public SetupMigration(SourceMigration sourceMigration, Func <SqlConnection, T> fn)
 {
     _sourceMigration = sourceMigration;
     _fn = fn;
 }
 public TargetMigration(SourceMigration sourceMigration, Func <SqlConnection, T> fn, string migrationName)
 {
     _sourceMigration = sourceMigration;
     _fn            = fn;
     _migrationName = migrationName;
 }