Added arn to the main repository

arn/HasID.go

@@ -0,0 +1,11 @@
+package arn
+
+// hasID includes an object ID.
+type hasID struct {
+	ID string `json:"id"`
+}
+
+// GetID returns the ID.
+func (obj *hasID) GetID() string {
+	return obj.ID
+}