Geo: Create an alias to connect to the Geo tracking DB via psql

We should make it easier for an admin to connect to the Geo tracking DB. Right now I have this stored away:

sudo -u gitlab-psql /opt/gitlab/embedded/bin/psql -h /var/opt/gitlab/geo-postgresql -p 5431 -d gitlabhq_geo_production

Ideally, we could run rails geo:dbconsole, but it looks like these are not meant to be extended without monkey patching: https://github.com/rails/rails/blob/v4.2.8/railties/lib/rails/commands/commands_tasks.rb