This PR uses the new syntax for commands introduced in Docker 1.13, making it a bit easier to understand just what a particular command is trying to do.
This also pushes the long-form syntax for docker command flags, which are also easier to understand at a glance.
This change allows operators to specify a DOCKER_BIN environment variable. This will specify a binary to run when executing docker, which is useful in cases where the 'docker' command being run must be modified in a way that would otherwise be invasive to Dokku, but minimalistic if done within a wrapper.
While I do not agree with _every_ style change, this will force Dokku to have consistent formatting across all shell scripts, which is arguably a Good Thing™.
The command used to reprocess everything is:
```shell
shfmt -l -bn -ci -i 2 -w .
```
Often-times, we will want to have the container inspect output for debugging purposes, but this process is:
- error prone, as the user needs to know what their containers are
- potentially insecure, as the output must be sanitized of sensitive data
Instead of making users wade through this process, we provide a helper `ps:inspect` command, that can be used to diagnose problems associated with containers that may or may not exist for an application.
This allows users to quickly show the state of any configured application, as well as the state of their server. In doing so, we make it easy for them to provide information necessary for debugging in a single command.
The correct way to handle getting the status should be ps:report.
Also cleaned up an issue where ps:report failed to catch errors for non-running containers.
The tags and tar plugins do not necessarily build from source, and running `ps:rebuild` can have some unexpected output in certain cases. Rather than try to handle that complexity - it's a lot - documenting the edge cases is the most appropriate way forward.
Applications without a restart-policy will have their policies set to `on-failure:10`. Users can completely unset the restart-policy using the `docker-options` plugin, though this will be equivalent to setting it explicitly to `no`.
Restart policies must be explicitly set, and the following are all valid:
- no
- unless-stopped
- always
- on-failure
- on-failure:NUMBER
