[WIP] Add a simple anonymous API to retrieve member org info

Hive NYC would like the [current member list](http://hivenyc.org/members/) on their Wordpress-based website to be pulled directly from the directory, so they don't have to maintain it in two separate places.

One way to support this is to add a simple API endpoint, e.g.:

```
GET /api/v1/cities/:city/members
```

This could return a JSON response such as:

```json
[
            {"name": "American Museum of Natural History",
             "website": "http://www.amnh.org/"},
            {"name": "WNYC's Radio Rookies",
             "website": "http://www.radiorookies.org/"},
]
```

A simple WordPress plugin or JS include on the Hive NYC site could then grab this JSON and drop it into a template.