eager not setted at first creation

[elicas]

Description

It would be nice to immediatly have the eager populated as soon as the object is created in order to avoid to make a find just after create to retreive the data.
For example, when we create a book for Mark it would be usefull to know that it's Mark's book and not only the book of "uuid".

Steps to Reproduce the Problem

I wrote directly in a test what it would be useful to have. The name of the test is not relevant, it's just because it's easier to explain and I think more understandable for you. (this function is in "preload_associations_test.go" line 10).

func Test_New_Implementation_For_Nplus1(t *testing.T) {
	if PDB == nil {
		t.Skip("skipping integration tests")
	}
	transaction(func(tx *Connection) {
		a := require.New(t)
		for _, name := range []string{"Mark", "Joe", "Jane"} {
			user := User{Name: nulls.NewString(name)}
			a.NoError(tx.Create(&user))

			book := Book{UserID: nulls.NewInt(user.ID)}
			a.NoError(tx.Create(&book))

			// THE COMMENTS TO READ
			// 1: a.Equal(user.ID, book.UserID.Int, "this is ok")
			// 2a: a.Equal(user.ID, book.User.ID, "but it would be cool to have it like that")
			// 2b: a.Equal(user.Name, book.User.Name, "in order to directly have the name for example")

			writer := Writer{Name: "Larry", BookID: book.ID}
			a.NoError(tx.Create(&writer))

			if name == "Mark" {
				song := Song{UserID: user.ID}
				a.NoError(tx.Create(&song))

				address := Address{Street: "Pop"}
				a.NoError(tx.Create(&address))

				home := UsersAddress{UserID: user.ID, AddressID: address.ID}
				a.NoError(tx.Create(&home))
			}
		}

		users := []User{}
		a.NoError(tx.All(&users))

		// FILL THE HAS-MANY and HAS_ONE
		a.NoError(preload(tx, &users))

		a.Len(users[0].Books, 1)
		a.Len(users[1].Books, 1)
		a.Len(users[2].Books, 1)
		a.Equal(users[0].FavoriteSong.UserID, users[0].ID)
		a.Len(users[0].Houses, 1)

		book := Book{}
		a.NoError(tx.First(&book))
		a.NoError(preload(tx, &book))
		a.Len(book.Writers, 1)
		a.Equal("Larry", book.Writers[0].Name)
		a.Equal("Mark", book.User.Name.String)
	})
}

Expected Behavior

To have the information of the book's owner, so the two lines in comments: 2a and 2b.

Actual Behavior

We only have the first line in comments: 1.

Info

I am with Linux and using v5.3.1 of Pop through v0.16.17 of Buffalo