feat(models): Support nested groups

models/contract.go

@@ -14,7 +14,10 @@ type Runner struct {
 }
 
 type Group struct {
-	Name string `json:"name" validate:"required"`
+	Name        string `json:"name" validate:"required"`
+	ParentGroup struct {
+		Name string `json:"name" validate:"required"`
+	} `json:"parent_group" validate:"optional"`
 }
 
 type ContractTemplateOptions struct {