code: func (q *Query) Eager(fields ...string) *Query {
  	q.eager = true
  	q.eagerFields = append(q.eagerFields, fields...)
  	return q
  }
docs: // Eager will enable load associations of the model.
  // by defaults loads all the associations on the model,
  // but can take a variadic list of associations to load.
  //
  // 	q.Eager().Find(model, 1) // will load all associations for model.
  // 	q.Eager("Books").Find(model, 1) // will load only Book association for model.