Express as a Dependency

[wagnerjt]

Hello Vikpe.

First, awesome repo. It is very similar to what I have going on privately. But I wanted to add a few things that I have discovered to be a bit more flexible for CI and deploying on containers.

My edits:

1. Express is now marked as a Dependency instead of a Dev Dependency.
   • Essentially this allows people to perform a npm prune --production to remove all of the dev dependencies on builds before they perform a release. This ensures a smaller disk size needed for any deployments, which is really nice for docker containers. Unfortunately, I have not found a yarn equivalent to perform this same action.
2. Made Express listen to an optional Environment Variable set for the Port
3. Added a bit more documentation

As a side note, if you accept this, I would happily do the same for your other repos listed in the README.

Feel free to add any questions 💯