Updated package json with preinstall script.
Updated package json with preinstall script.

codeforboston/bostongreenmap,codeforboston/bostongreenmap,varmas/bostongreenmap,varmas/bostongreenmap,varmas/bostongreenmap,codeforboston/bostongreenmap,codeforboston/bostongreenmap,varmas/bostongreenmap,codeforboston/bostongreenmap,varmas/bostongreenmap