add executable bit to the script

This commit adds executable bit to the script since it is an executable.
The example in the README.md will fail if this patch is not applied.

Signed-off-by: Ｖ字龍(Vdragon) <Vdragon.Taiwan@gmail.com>
Merge pull request #6 from Vdragon/fix_x_bit_issue

add executable bit to the script