update README for docker instructions
update README for docker instructions

Code4Maine/wheresyourtrash,mainecivichackday/wheresyourtrash,mainecivichackday/wheresyourtrash,mainecivichackday/wheresyourtrash,mainecivichackday/wheresyourtrash,Code4Maine/wheresyourtrash,Code4Maine/wheresyourtrash,Code4Maine/wheresyourtrash