Update usage section to allow command line arguments
Update usage section to allow command line arguments

CMD was changed to ENTRYPOINT, the USAGE section didn't reflect this change
ricardorsierra/dockerfiles,koep/dockerfiles,jessfraz/dockerfiles,saneax/dockerfiles,alanbrent/dockerfiles,konstruktoid/dockerfiles,johnsandiford/dockerfiles,konstruktoid/dockerfiles,ricardorsierra/dockerfiles,rothgar/dockerfiles,alanbrent/dockerfiles,michael-k/dockerfiles-jfrazelle,koep/dockerfiles,rothgar/dockerfiles,koep/dockerfiles,jessfraz/dockerfiles,saneax/dockerfiles,konstruktoid/dockerfiles,koep/dockerfiles,johnsandiford/dockerfiles,johnsandiford/dockerfiles,michael-k/dockerfiles-jfrazelle,johnsandiford/dockerfiles,alanbrent/dockerfiles,jessfraz/dockerfiles,ricardorsierra/dockerfiles,ricardorsierra/dockerfiles,koep/dockerfiles,michael-k/dockerfiles-jfrazelle,ricardorsierra/dockerfiles,jfrazelle/dockerfiles,johnsandiford/dockerfiles,jessfraz/dockerfiles,konstruktoid/dockerfiles,jessfraz/dockerfiles,jfrazelle/dockerfiles,rothgar/dockerfiles,michael-k/dockerfiles-jfrazelle,michael-k/dockerfiles-jfrazelle