Document Yokozuna

Yokozuna, or Search 2, must be as thoroughly documented as Riak Search currently is. That means detailed documentation on:

- [ ] Ops: Installation
- [ ] Ops: Configuration
- [ ] Dev: Schema creation
- [ ] Dev: Index creation
- [ ] Dev: Querying (can be basic, advanced queries can be found in the solr docs)

That's a minimum set, anything more is gravy, such as:

- [ ] Differences between YZ and RS
- [ ] Known Issues and Gotchas