fix restore from old backup to updated trackimpl. (#1269)

* fix restore from old backup to updated trackimpl.
added backup of tracking url for new backups

* assignment not needed

app/src/main/java/eu/kanade/tachiyomi/data/backup/serializer/TrackTypeAdapter.kt

@@ -14,6 +14,7 @@ object TrackTypeAdapter {
     private const val REMOTE = "r"
     private const val TITLE = "t"
     private const val LAST_READ = "l"
+    private const val TRACKING_URL = "u"
 
     fun build(): TypeAdapter<TrackImpl> {
         return typeAdapter {
@@ -27,6 +28,8 @@ object TrackTypeAdapter {
                 value(it.remote_id)
                 name(LAST_READ)
                 value(it.last_chapter_read)
+                name(TRACKING_URL)
+                value(it.tracking_url)
                 endObject()
             }
 
@@ -42,6 +45,7 @@ object TrackTypeAdapter {
                             SYNC -> track.sync_id = nextInt()
                             REMOTE -> track.remote_id = nextInt()
                             LAST_READ -> track.last_chapter_read = nextInt()
+                            TRACKING_URL -> track.tracking_url = nextString()
                         }
                     }
                 }

app/src/main/java/eu/kanade/tachiyomi/data/database/models/TrackImpl.kt

@@ -20,7 +20,7 @@ class TrackImpl : Track {
 
     override var status: Int = 0
 
-    override lateinit var tracking_url: String
+    override var tracking_url: String = ""
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true