Add VCR.
Remove cucumber.
Fix bug in `Model#clean_json`.

The API Session Token endpoint returns an object like this:

```json
{
  "token": "abcd1234",
  "ttl": 1200,
  "user_id": 13
}
```

And `clean_json` was being a little overzealous and just returning
`"abcd1234"` which was causing token retrieval to fail.  This wasn't
caught by units, which is why I am writing this acceptance suite, eh?
Fix token expiry and make it actually work as advertised.
First pass at adding acceptance tests with VCR.
Re-record on CI, never otherwise.
Rename spec.
Fix bug where class methods were not being extended.
Add authentic? predicate.
Merge branch 'acceptance-tests' of github.com:OSHPark/ruby-api-client into acceptance-tests
Add an API workflow test.