add disk cache settings

server/settings/btsets.go

@@ -11,6 +11,8 @@ type BTSets struct {
 	CacheSize        int64 // in byte, def 200 mb
 	PreloadBuffer    bool
 	ReaderReadAHead  int // in percent, 5%-100%, [...S__X__E...] [S-E] not clean
+	UseDisk          bool
+	TorrentsSavePath string
 
 	// Torrent
 	ForceEncrypt             bool