refactor(training): make TrainingID a type alias of uuid.UUID, not new type

pkg/training/model.go

@@ -1,32 +1,13 @@
 package training
 
 import (
-	"encoding/json"
-
 	"github.com/google/uuid"
 )
 
-type TrainingID uuid.UUID
+type TrainingID = uuid.UUID
 
 func NewTrainingID() TrainingID {
-	return TrainingID(uuid.Must(uuid.NewV7()))
-}
-
-func (id TrainingID) String() string {
-	return uuid.UUID(id).String()
-}
-
-func (id TrainingID) MarshalJSON() ([]byte, error) {
-	return json.Marshal(uuid.UUID(id))
-}
-
-func (id *TrainingID) UnmarshalJSON(data []byte) error {
-	var u uuid.UUID
-	if err := json.Unmarshal(data, &u); err != nil {
-		return err
-	}
-	*id = TrainingID(u)
-	return nil
+	return uuid.Must(uuid.NewV7())
 }
 
 type Training struct {