readme: Add install docs for npm
readme: Add install docs for npm

chrismoulton/DropKick,GerHobbelt/DropKick,alexgleason/DropKick,Robdel12/DropKick,GerHobbelt/DropKick,Robdel12/DropKick,chrismoulton/DropKick,acebalajadia/DropKick,alexgleason/DropKick,alex-riabenko/DropKick,acebalajadia/DropKick,alex-riabenko/DropKick