typo

mujson_mgr.py

@@ -29,7 +29,7 @@ class MuJsonLoader(object):
 			output = json.dumps(self.json, sort_keys=True, indent=4, separators=(',', ': '))
 			with open(path, 'a'):
 				pass
-			with open(path, 'r+') as f:
+			with open(path, 'rb+') as f:
 				f.write(output.encode('utf8'))
 				f.truncate()