Since we use the `PORT` env var to configure the port, this value will
often be out of date. It leads to some confusing output in, for example
`docker-compose ps` when using a port other than the default:
```
julian@manhattan ~/repos/pelias/dockerfiles $ docker-compose ps
Name Command State Ports
---------------------------------------------------------------------------------------------------------------------
pelias_api ./bin/start Up 3100/tcp, 0.0.0.0:4000->4000/tcp
```
Notice how the Ports section shows 3100, even though nothing is running
on that port in the container, because the `PORT` env var was set to
4000.
There were a couple problems with the current dockerfile:
* It set the userid of the processes running in the container to 9999,
without creating a user with that ID. This leads to confusion and an
annoying message when you run an interactive bash session (the shell PS1
would display something like `I have no name!@1438586f786e:~$`
* It tried to run `chown` on _all_ code files after running NPM install.
This takes a really long time
* It did not copy `package.json` and run `npm install` before copying
other files. This means even a one line code change causes the image
rebuild process to re-run `npm install`, which takes 30 seconds or so
Now the image creates and uses a pelias user, sets permissions correctly
from the start to avoid `chown`, and only runs `npm install` when it
absolutely has to.
Julian Simioni
Rhys Kidd
Julian Simioni
Peter Johnson
Amir Rahnama
Hannes Junnila