LDB service forgets about stations if it's started before the reference service

[peter-mount]

This happened this morning after Linode did some maintenance and rebooted the server.

The ldb service came up before the ref service so when it went off to get the current list of stations it failed so all requests for departure boards returned nothing.

Nothing showed up wrong in the grafana dashboards as it was receiving data from the d3 service so the boards were there just inaccessible until I restarted the service again.

This is probably an issue from when ldb stored everything in ram so it should still do this check on startup but not remove all references its got in its own db