refactors data access layer to use pop ORM for eager loading, adds book titles rented to renters in response body

bookish-server/models/rental.go

@@ -0,0 +1,19 @@
+package models
+
+import (
+	"time"
+
+	"github.com/gobuffalo/nulls"
+	"github.com/gobuffalo/uuid"
+)
+
+type Rental struct {
+	ID         uuid.UUID  `db:"id"`
+	CreatedAt  time.Time  `db:"created_at"`
+	UpdatedAt  time.Time  `db:"updated_at"`
+	BookTitle  string     `db:"book_title"`
+	RenterID   uuid.UUID  `db:"renter_id"`
+	RentalDate time.Time  `db:"rental_date"`
+	ReturnDate nulls.Time `db:"return_date"`
+	Renter     *Renter    `belongs_to:"renter"`
+}