add script to clean Yum cache
add script to clean Yum cache

ChicagoBoothAnalytics/DataWrangling_inR,ChicagoBoothAnalytics/HelpRFun,ChicagoBoothAnalytics/DataWrangling_inR,ChicagoBoothAnalytics/DataWrangling_inR,ChicagoBoothAnalytics/HelpRFun,ChicagoBoothAnalytics/HelpRFun