install & config mysql.sh

### install mysql
sudo apt-get update
sudo apt-get install mysql-server
# if you ignore the root's password setting, do
# sudo mysql_secure_installation


## under mysql 5.7, do extra: 
# sudo mysql_install_db

# note: mysql 5.5 on ubuntu 14, mysql 5.7 on ubuntu 16

## done, then check
# with 5.5
service mysql status

# with 5.7
systemctl status mysql.service

# with both version, you can do extra check by mysqladmin
mysqladmin -p -u root version




### config mysql (TODO)