Refactor to collect all books in a category

Signed-off-by: Marcus Noble <github@marcusnoble.co.uk>

main.go

@@ -27,7 +27,7 @@ func init() {
 }
 
 func main() {
-	latestBooks := map[string]*storygraph.Book{}
+	latestBooks := map[string]*[]storygraph.Book{}
 	refreshingBooks := true
 	var lastUpdated *time.Time
 
@@ -41,9 +41,9 @@ func main() {
 		}
 
 		// Update each category individually with books we have managed to find
-		for cat, book := range newBookList {
+		for cat, books := range newBookList {
 			if b, ok := newBookList[cat]; ok && b != nil {
-				latestBooks[cat] = book
+				latestBooks[cat] = books
 			}
 		}
 		now := time.Now()
@@ -60,7 +60,7 @@ func main() {
 
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		type data struct {
-			Books       map[string]*storygraph.Book
+			Books       map[string]*[]storygraph.Book
 			LastUpdated string
 			Refreshing  bool
 		}