update

src/db/model/material.go

@@ -62,6 +62,7 @@ type Image struct {
 // Background represents the background material model that exactly matches the JSON structure
 type Material struct {
 	Id         primitive.ObjectID `bson:"_id,omitempty" json:"_id,omitempty"`
+	Cid        primitive.ObjectID `bson:"cid,omitempty" json:"cid,omitempty"`
 	ID         int                `bson:"id,omitempty" json:"id,omitempty"`
 	Type       int                `bson:"type,omitempty" json:"type,omitempty"`
 	Attributes struct {