Add option for overwriting database rating

src/core/song.cpp

@@ -1680,13 +1680,13 @@ void Song::ToXesam(QVariantMap *map) const {
 
 }
 
-void Song::MergeUserSetData(const Song &other) {
+void Song::MergeUserSetData(const Song &other, const bool merge_rating) {
 
   if (other.playcount() > 0) {
     set_playcount(other.playcount());
   }
 
-  if (other.rating() > 0) {
+  if (merge_rating && other.rating() > 0.0F) {
     set_rating(other.rating());
   }
 

src/core/song.h

@@ -187,7 +187,7 @@ class Song {
 
   // Copies important statistics from the other song to this one, overwriting any data that already exists.
   // Useful when you want updated tags from disk but you want to keep user stats.
-  void MergeUserSetData(const Song &other);
+  void MergeUserSetData(const Song &other, const bool merge_rating);
 
   // Save
   void BindToQuery(SqlQuery *query) const;