has many to many progress

test/models/recipe.hpp

@@ -18,6 +18,10 @@ struct ingredient
   std::string name;
   std::vector<object::object_ptr<recipe>> recipes{};
 
+  ingredient()= default;
+  ingredient(const unsigned int id, std::string name)
+    : id(id), name(std::move(name)) {}
+
   template<class Operator>
   void process(Operator &op) {
     namespace field = matador::access;
@@ -33,6 +37,10 @@ struct recipe
   std::string name;
   std::vector<object::object_ptr<ingredient>> ingredients{};
 
+  recipe()= default;
+  recipe(const unsigned int id, std::string name)
+  : id(id), name(std::move(name)) {}
+
   template<class Operator>
   void process(Operator &op) {
     namespace field = matador::access;