Running keybase in a container

Hi, i'm trying to get keybase running in a container, as I'm a fedora atomic linux user. The cli works great however I'm having a little trouble with the GUI starting, and i'm not exactly sure how to debug it, so maybe you have some ideas.

Dockerfile
```
FROM fedora

RUN dnf install -y https://prerelease.keybase.io/keybase_amd64.rpm && \
adduser -u 1000 developer

USER 1000
WORKDIR /home/developer

CMD ["run_keybase"]

```

Building this and then running with
`docker run --rm -v /tmp/.X11-unix:/tmp/.X11-unix -v /home/${USER}:/home/developer -e DISPLAY=${DISPLAY} --security-opt label=type:container_runtime_t tomwhiston/keybase:latest` produces the following output, but no GUI is started
```
Shutting down keybase service...
Launching keybase service...
Mounting the file system...
Launching Keybase GUI...
Success!
```

Start with the Dockerfile and the provided docker run command, then reproduce the successful-looking GUI launch that produces no visible window. Investigate the container's display setup and GUI startup behavior; done means the Keybase GUI launches visibly from the container.

Written by the indexing model from the issue text.