Update DeveloperGuide.md
Update DeveloperGuide.md
lproperty/main,kennyngdsc/addressbook-level4,kennyngdsc/addressbook-level4,Manish1Dahiya/main,Manish1Dahiya/main,lproperty/main,CS2103JAN2017-T15-B3/main,CS2103JAN2017-T15-B3/main