Usage

$ todo add 2 hello world    # Add a todo with priority 2
$ todo ls                   # Show all incompleted todos sorted by priority in ascending order
$ todo ls --format          # --format for formatting
$ todo ls --done            # Show all completed todos sorted by priority in ascending order
$ todo del ID               # Delete a completed todo with the given ID
$ todo del ID --force       # Use --force flag to delete a uncompleted todo
$ todo del --all            # Delete all completed todo
$ todo done ID              # Mark the incomplete todo with the given ID as complete
$ todo done ID --undone     # Mark the complete todo with the given ID as incomplete
$ todo report               # Statistics
$ todo help                 # Show usage