Data: add realm-cocoa

# Realm

Realm is a mobile database that runs directly inside phones, tablets or wearables.
This repository holds the source code for the iOS & OSX versions of Realm, for both Swift & Objective-C.


## Features

* **Mobile-first:** Realm is the first database built from the ground up to run directly inside phones, tablets and wearables.
* **Simple:** Data is directly [exposed as objects](http://realm.io/docs/cocoa/#models) and [queryable by code](http://realm.io/docs/cocoa/#queries), removing the need for ORM's riddled with performance & maintenance issues. Plus, we've worked hard to [keep our API down to just 3 common classes](http://realm.io/docs/cocoa/api/) (Object, Arrays and Realms) and 1 utility class (Migrations): most of our users pick it up intuitively, getting simple apps up & running in minutes.
* **Modern:** Realm supports relationships, generics, vectorization and even Swift (experimental).
* **Fast:** Realm is faster than even raw SQLite on common operations, while maintaining an extremely rich feature set.