addRelation

lets add addRelation functions:

Example 
    
const addCityCountryValidator = () => {
  return object({
    set: object({
      city: objectIdValidation,
      country: objectIdValidation,
      isCapital: boolean(),
    }),
    get: coreApp.schemas.selectStruct("city", 1),
  });
};

const addCityCountry: ActFn = async (body) => {
const { country, city, isCapital } = body.details.set;



  return await cities.addRelation({
    filters: { _id: new ObjectId(city) },
    projection: body.details.get,
    relations: {
      country: {
        _ids: new ObjectId(country),
        relatedRelations: {
          citiesAsc: true,
          citiesDesc: true,
          citiesByPopAsc: true,
          citiesByPopDesc: true,
          capitalCity: isCapital,
        },
      },
    },
    replace: true,
  });
  

};
coreApp.acts.setAct({
  schema: "city",
  actName: "addCityCountry",
  validator: addCityCountryValidator(),
  fn: addCityCountry,
});

addRelations functions accept three inputs:

Return Of Example: 
    
    {
      body: {
        _id: 65a3dfe5b7f33fd5950b9345,
        name: Harat,
        population: 1800000,
        abb: HAR,
        country: {
          _id: 65a3dfe5b7f33fd5950b9342,
          name: Afghanistan,
          population: 15000000,
          abb: AFG
        }
      },
      success: true
    }