add missing lfs config on example file (#2039)

* add missing lfs config on example file

* leveal jwt secret empty

conf/app.ini

@@ -147,6 +147,12 @@ APP_DATA_PATH = data
 ENABLE_GZIP = false
 ; Landing page for non-logged users, can be "home" or "explore"
 LANDING_PAGE = home
+; Enables git-lfs support. true or false, default is false.
+LFS_START_SERVER = false
+; Where your lfs files put on, default is data/lfs.
+LFS_CONTENT_PATH = data/lfs
+; LFS authentication secret, changed this to yourself.
+LFS_JWT_SECRET   = 
 
 ; Define allowed algorithms and their minimum key length (use -1 to disable a type)
 [ssh.minimum_key_sizes]