Check if there is any author before using the first

- Closes: #26

lib/admin.go

@@ -68,7 +68,11 @@ func editHandler(h handler) {
 	var data bookData
 	data.Book = book
 	data.S = GetStatus(h)
-	data.S.Title = book.Title + " by " + book.Author[0] + " -- Edit -- " + data.S.Title
+	author := ""
+	if len(book.Author) > 0 {
+		author = " by " + book.Author[0]
+	}
+	data.S.Title = book.Title + author + " -- Edit -- " + data.S.Title
 	h.template.load(h, "edit", data)
 }
 

lib/reader.go

@@ -157,7 +157,13 @@ func readHandler(h handler) {
 
 	var data readData
 	data.S = GetStatus(h)
-	data.S.Title = book.Title + " by " + book.Author[0] + " -- Read -- " + data.S.Title
+
+	author := ""
+	if len(book.Author) > 0 {
+		author = " by " + book.Author[0]
+	}
+	data.S.Title = book.Title + author + " -- Read -- " + data.S.Title
+
 	data.Book = book
 	if !book.Active {
 		data.Back = "/new/"

lib/trantor.go

@@ -66,7 +66,13 @@ func bookHandler(h handler) {
 		return
 	}
 	data.Book = book
-	data.S.Title = book.Title + " by " + book.Author[0] + " -- " + data.S.Title
+
+	author := ""
+	if len(book.Author) > 0 {
+		author = " by " + book.Author[0]
+	}
+	data.S.Title = book.Title + author + " -- " + data.S.Title
+
 	data.Description = strings.Split(data.Book.Description, "\n")
 	data.FlaggedBadQuality = false
 	for _, reporter := range book.BadQualityReporters {