diff --git a/server/models/song.js b/server/models/song.js
index c4f372a5..5319be34 100644
--- a/server/models/song.js
+++ b/server/models/song.js
@@ -11,7 +11,7 @@ const SongSchema = new Schema({
     type: Schema.Types.ObjectId,
     ref: 'lyric'
   }]
-});
+}, { usePushEach: true });
 
 SongSchema.statics.addLyric = function(id, content) {
   const Lyric = mongoose.model('lyric');