add coding style config file.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
install grunt cli automatically via npm install command.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Merge pull request #2 from appleboy/patch-2

install grunt cli automatically via npm install command.
Merge pull request #1 from appleboy/patch-1

add coding style config file.