Added canonical title diff

utils/AnimeGenresDiff.go

@@ -0,0 +1,24 @@
+package utils
+
+import "strings"
+
+// AnimeGenresDiff describes differing genres.
+type AnimeGenresDiff struct {
+	GenresA []string
+	GenresB []string
+}
+
+// String returns the description.
+func (diff *AnimeGenresDiff) String() string {
+	return "Genres are different"
+}
+
+// DetailsA shows the details for the first anime.
+func (diff *AnimeGenresDiff) DetailsA() string {
+	return strings.Join(diff.GenresA, ", ")
+}
+
+// DetailsB shows the details for the second anime.
+func (diff *AnimeGenresDiff) DetailsB() string {
+	return strings.Join(diff.GenresB, ", ")
+}