Upstart conf's should exist in /etc/init instead of /etc/init.d

Add `-C` option to specify the working directory

The concrete goal of adding this switch is to be able to start a runner as:

```
/opt/gitlab-runner/bin/runner -C /home/gitlab-runner
```

This way we can keep the runner's executable code under `/opt/gitlab-runner`, owned by root, and have `/home/gitlab-runner` (or whatever we come up with) as a writable, working area for the gitlab-ci-runner user.

This new switch does not change the default behavior of the runner.

See merge request !14

bin/setup needs bundler too

By adding `require 'bundler/setup'` we remove the need for `bundle exec`.
This is already done in the other scripts in bin/; this change adds the
missing require to bin/setup.

See merge request !13

By adding `require 'bundler/setup'` we remove the need for `bundle
exec`. This is already done in the other scripts in bin/; this change
adds the missing require to bin/setup.

Add HOME to the Upstart config example

This seems to be a good idea.

See merge request !12

Add Upstart config

Upstart takes care of respawning and logging. This only works for
distributions that use Upstart, such as Ubuntu 12.04, Ubuntu 14.04
and Centos 6.

See merge request !11

Dockerfile update

Moves mysql, redis and postgresql to optional dependencies section. Postgresql version number was updated from 9.1 to 9.3 (Available in Ubuntu 14.04).

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Drop ssh keygen

Runner use http to clone repo from source so its no need in ssh key for
it

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Tempfile permissions

Fix typos in Dockerfile

Make sure we submit completed build to coordinator.

Merge branch 'ansynchronous-build' of https://github.com/gucki/gitlab-ci-runner into gucki-ansynchronous-build

Dockerfile fixed to avoid error on Upstart workaround

Add Cloud Runner

/cc @dzaporozhets

Small guide on how to add a runner to our setup.