Add Monetization property to Object struct

activitystreams/activity.go

@@ -142,7 +142,7 @@ type Object struct {
 	Endpoints         *Endpoints `json:"endpoints,omitempty"`
 
 	// Extensions
-	// NOTE: add extensions here
+	Monetization string `json:"monetization,omitempty"`
 }
 
 // NewNoteObject creates a basic Note object that includes the public
@@ -182,3 +182,8 @@ func NewPersonObject() *Object {
 	}
 	return &o
 }
+
+func (o *Object) AddWebMonetization(wallet string) {
+	o.Context = append(o.Context, apMonetizationContext)
+	o.Monetization = wallet
+}