display additional columns for databaseuserreferences

[kperath]

Fixes #18

$ k -n my-application get databaseuserreferences
NAME                 AGE   CLUSTER NAME       USERNAME   ROLE
my-app-db-user-ref   67m   my-referenced-db   doadmin    primary

[adamwg]

What happens if we specify .spec.databaseCluster here rather than just the name? It would be nice to see the type as well, but I'm not sure it deserves its own column. Wondering if it will pretty-print it in a reasonable way if we just tell it to print the whole object reference.

[kperath]

This is what it looks like without the name

 NAME                 AGE     CLUSTER NAME                                                                                            USERNAME   ROLE
my-app-db-user-ref   3d17h   {"apiGroup":"databases.digitalocean.com","kind":"DatabaseClusterReference","name":"my-referenced-db"}   doadmin    primary

[adamwg]

Ah, that's gross. Let's stick with what's already in this PR.

[adamwg]

lgtm