Merge pull request #1 from happyyi008/rollback-unless-committed

Add RollBackUnlessCommitted to interface

igorm.go

@@ -56,6 +56,7 @@ type Gormw interface {
 	Begin() Gormw
 	Commit() Gormw
 	Rollback() Gormw
+	RollbackUnlessCommitted() Gormw
 	NewRecord(value interface{}) bool
 	RecordNotFound() bool
 	CreateTable(values ...interface{}) Gormw
@@ -302,6 +303,10 @@ func (it *gormw) Rollback() Gormw {
 	return Wrap(it.w.Rollback())
 }
 
+func (it *gormw) RollbackUnlessCommitted() Gormw {
+	return Wrap(it.w.RollbackUnlessCommitted())
+}
+
 func (it *gormw) NewRecord(value interface{}) bool {
 	return it.w.NewRecord(value)
 }