Review Board 6's documentation update for Docker broke the default Nginx

template, causing a default install to fail to load static media.
The content was copied from the sample documented Nginx template used

for a Review Board site install, but the paths were wrong for a Docker

install.
This change updates the paths to point to the right location.

Compared this to the working configuration in Review Board 5 and my

test copy of the docker-compose file.