Current docker build output: /bin/sh: 1: locale-gen: not found
Locale-gen is not provided anymore by ubuntu base image, so it must be installed beforehand.
To reduce the Docker image size a seperate build Dockerfile is
introduced. This Docker image produces a tarball of the released and
compiled software which can when be piped into the Dockerfile.run build
process. The result is a minimal image only containing Spreed WebRTC and
the gear to run OpenSSL.
First create the builder image:
```
docker build -t spreed-webrtc-builder -f Dockerfile.build .
```
Next run the builder container, piping its output into the creation of
the runner container:
```
docker run --rm spreed-webrtc-builder | docker build -t spreed-webrtc -f
Dockerfile.run -
```
Afterwards run the container like this:
```
docker run --rm --name my-spreed-webrtc -p 8080:8080 -p 8443:8443 \
-v `pwd`:/srv/extra -i -t spreed-webrtc
```