added units example to docs
added units example to docs

TrangPham/geocoder,sideci-sample/sideci-sample-geocoder,jaigouk/geocoder-olleh,crdunwel/geocoder,ivanzotov/geocoder,rdlugosz/geocoder,tiramizoo/geocoder,aceunreal/geocoder,jgrciv/geocoder,sjaveed/geocoder,Devetzis/geocoder,mveer99/geocoder,guavapass/geocoder,gogovan/geocoder-olleh,tortuba/geocoder,davydovanton/geocoder,epyatopal/geocoder,ankane/geocoder,andreamazz/geocoder,mehlah/geocoder,boone/geocoder,malandrina/geocoder,StudioMelipone/geocoder,donbobka/geocoder,jaigouk/geocoder-olleh,brian-ewell/geocoder,FanaHOVA/geocoder,AndyDangerous/geocoder,sr-education/geocoder,eugenehp/ruby-geocoder,rios1993/geocoder,gogovan/geocoder-olleh,moofish32/geocoder,rayzeller/geocoder,GermanDZ/geocoder,3mundi/geocoder,alexreisner/geocoder,mdebo/geocoder