return album genres as a list of objects as per opensubsonic

https://github.com/opensubsonic/open-subsonic-api/pull/51

server/ctrlsubsonic/spec/construct_by_tags.go

@@ -44,7 +44,7 @@ func NewAlbumByTags(a *db.Album, artists []*db.Artist) *Album {
 		ret.Genre = a.Genres[0].Name
 	}
 	for _, g := range a.Genres {
-		ret.Genres = append(ret.Genres, g.Name)
+		ret.Genres = append(ret.Genres, &GenreRef{Name: g.Name})
 	}
 	return ret
 }

server/ctrlsubsonic/spec/spec.go

@@ -116,6 +116,10 @@ type ArtistRef struct {
 	Name string     `xml:"name,attr" json:"name"`
 }
 
+type GenreRef struct {
+	Name string `xml:"name,attr" json:"name"`
+}
+
 type Album struct {
 	// common
 	ID       *specid.ID   `xml:"id,attr,omitempty"       json:"id"`
@@ -134,7 +138,7 @@ type Album struct {
 	TrackCount int           `xml:"songCount,attr"         json:"songCount"`
 	Duration   int           `xml:"duration,attr"          json:"duration"`
 	Genre      string        `xml:"genre,attr,omitempty"   json:"genre,omitempty"`
-	Genres     []string      `xml:"genres,omitempty"       json:"genres,omitempty"`
+	Genres     []*GenreRef   `xml:"genres,omitempty"       json:"genres,omitempty"`
 	Year       int           `xml:"year,attr,omitempty"    json:"year,omitempty"`
 	Tracks     []*TrackChild `xml:"song,omitempty"         json:"song,omitempty"`
 	// star / rating