update readme file with docker instruction

[ratanparai]

I'm submitting a...

[ ] Bug report  
[ ] Performance issue
[ ] Feature request
[x] Documentation issue or request
[ ] Other... Please describe:

Current behavior

After the docker integration in PR #53, now you can run the Academia app in Docker container. But there is no easy to follow instruction how to run it in Docker.

Expected behavior

There should be a easy to follow instruction to setup and run the project in docker container.