Add Dinesh Subhraveti to MAINTAINERS

Docker-DCO-1.1-Signed-off-by: Dinesh Subhraveti <dineshs@altiscale.com> (github: dineshs-altiscale)
Now using the nginx docker image instead of the apache one. dotcloud/docker/issues/6374

Docker-DCO-1.1-Signed-off-by: Julien Bordellier <me@julienbordellier.com> (github: jstoja)