Move db backup command into a script. In case of cron run it incorrectly.

Original one doesn't work because cron cannot parse command "mysqldump -utao -pKiBr11EY23nj --sock=/tmp/mysql.sock tao_production | gzip > /home/app/backups/tao_`date +'%Y-%m-%d-%T'`.sql.gz" correctly. it always run it as 

"mysqldump -utao -pKiBr11EY23nj --sock=/tmp/mysql.sock tao_production | gzip > /home/app/backups/tao_`date +'" the single quote treated as the end of the command that causes the command cannot run as expected.