Add tag type and tag alias.

server/model/tag.go

@@ -6,19 +6,30 @@ type Tag struct {
 	gorm.Model
 	Name        string `gorm:"unique"`
 	Description string
+	AliasOf     *uint `gorm:"default:NULL"` // Foreign key for aliasing, can be NULL
+	Type        string
 	Resources   []Resource `gorm:"many2many:resource_tags;"`
+	Aliases     []Tag      `gorm:"foreignKey:AliasOf;references:ID"`
 }
 
 type TagView struct {
-	ID          uint   `json:"id"`
-	Name        string `json:"name"`
-	Description string `json:"description"`
+	ID          uint     `json:"id"`
+	Name        string   `json:"name"`
+	Description string   `json:"description"`
+	Type        string   `json:"type"`
+	Aliases     []string `json:"aliases"`
 }
 
 func (t *Tag) ToView() *TagView {
+	aliases := make([]string, 0, len(t.Aliases))
+	for _, alias := range t.Aliases {
+		aliases = append(aliases, alias.Name)
+	}
 	return &TagView{
 		ID:          t.ID,
 		Name:        t.Name,
 		Description: t.Description,
+		Type:        t.Type,
+		Aliases:     aliases,
 	}
 }