An example app that listens on the PORT system variable

[tkvogt]

A lot of people want to quickly see if it works.
With this patch you just have to copy paste a line of bash and copy the generated bundle to /opt/keter/incoming and go to https://localhost

[jappeace]

Adding a servant example is probably a good idea, but how is this different from the examples in: https://github.com/snoyberg/keter/tree/master/incoming

Also rebase onto master to make ci pass

[tkvogt]

I was not aware that there are examples in the incoming folder. What is not good in my opinion is to say in the Readme: "Modify your web app to check for the PORT environment variable" and not saying how. I will update this pull request.

[jappeace]

I added an explicit link to that: #224

Your example is still welcome, it'd be nice if it would build with ci as well.