postgres:status can't find image

[audy]

I believe this is because the output of docker ps no longer has the contains the latest tag, causing this line to fail to find the image id: https://github.com/jeffutter/dokku-postgresql-plugin/blob/master/commands#L35.

I can submit a PR with a fix. I'm using this plugin for a lot of apps and don't want to switch right now 😄

On a related note, could I add an exit -1 here: https://github.com/jeffutter/dokku-postgresql-plugin/blob/master/commands#L107. The reason is that postgresql:dump_all stopped working because I upgraded Docker. I wasn't aware of this because my backup scripts weren't crashing.