Add the method to update a source path.

tui_rsync/models/models.py

@@ -94,6 +94,11 @@ class Source(BaseModel):
         self.label = new_label
         self.save()
 
+    def update_source_path(self, new_path):
+        new_source_path, _ = Path.get_or_create(path=new_path)
+        self.source = new_source_path
+        self.save()
+
     def update_args(self, args):
         args_obj = SyncCommand.get_sync_command(args)
         self.args = args_obj