For instructions, see `ldap.conf`

### Debugging
```
docker run -it --rm alpine /bin/sh -c "apk add openldap-clients;ldapsearch -x -b 'cn=users,dc=in-ulm,dc=de' -H 'ldap://ldap.in-ulm.de'"
```

### Old config which stopped working in Aug 2019
```
append_host_config:
  "in-ulm.de":
    auth_method: ldap
    ldap_servers:
      - "ldap.in-ulm.de"
    ldap_base: "cn=users,dc=in-ulm,dc=de"
```