[FEATURE-REQUEST] Have a way to call a custom attribute in show/edit/create

Hey there I'm wanting to show a custom read only field where I can populate it.

For example if I have an association submitter, and they submit and event I want to show their name and email on the event show page. Is there a way to do this right now?

for example
```elixir
submitter_name: %{
type: :string,
value: fn event->
event.submitter.name
end
}
```

Thank you in advance.