Update README.md

fix typo.

README.md

@@ -3,7 +3,7 @@ tunasync
 
 ## TODO
 
-- [ ] implement `tunasyctl tail` and `tunasynctl log` or equivalent feature
+- [ ] implement `tunasynctl tail` and `tunasynctl log` or equivalent feature
 - [x] status file
 - [x] btrfs backend (create snapshot before syncing)
 - [x] add mirror job online