Moving from slow to active_record helper

Before:

```shell
$ rspec spec/features/fedora_to_in_memory_spec.rb

Finished in 0.28749 seconds (files took 2.66 seconds to load)
```

After:

```shell
$ rspec spec/features/fedora_to_in_memory_spec.rb

Finished in 0.34651 seconds (files took 0.74007 seconds to load)
```