feat: add AddReference method to References

Signed-off-by: Yordis Prieto <[email protected]>

pkg/config/resource.go

@@ -169,6 +169,20 @@ type ExternalName struct {
 // given resource. Key should be the field path of the field to be referenced.
 type References map[string]Reference
 
+// AddReference adds a reference configuration for the given field path.
+// The fieldPath is the Terraform field path of the field to be referenced.
+//
+// Example: "vpc_id" or "forwarding_rule.certificate_name" in case of nested
+// in another object.
+func (r References) AddReference(fieldPath string, ref Reference) error {
+	if _, ok := r[fieldPath]; ok {
+		return fmt.Errorf("reference for field %s already exists", fieldPath)
+	}
+
+	r[fieldPath] = ref
+	return nil
+}
+
 // Reference represents the Crossplane options used to generate
 // reference resolvers for fields
 type Reference struct {