Content not being copied over for nginx container

Github repo

My Dockerfile:

FROM nginx
COPY sites-available-default /etc/nginx/sites-available/default
COPY app-dir /usr/share/nginx/html

where sites-available-default is the file and app-dir is a directory containing index.php

I was able to build and run container with steps:

docker build -t nginx-cont .
docker run --name nginx-cont -d -p 8080:80 nginx

and was able to check the nginx default page at
where is the docker-machine default ip.

Within from nginx-cont, I’ve confirmed that sites-available-default and the content of app-dir were not copied over. Where am I missing?