Add default expose port of 8080 to Dockerfile

[sammaphey]

I am trying to build integration tests through Gitlab Services but get an error because there is no default exposed port, as required by Gitlab CI.

This is easily solved by modifying the Dockerfile to expose port 8080:

# Build the docker file needed to construct integration tests.
FROM rwynn/monstache:latest

# The base image does not expose a port (gitlab CI requires an exposed port to run as a service).
EXPOSE 8080

Please add this default port so that I don't have to manually create a new docker image just to expose the port