Add a wiki

[wesharper]

Description
The README references a wiki, which doesn't appear to exist. While it's possible to piece together information using the API docs and some trial and error, it would be nice if there were exhaustive docs on the entire SDK api as well as common use cases and patterns including, but not limited to the following:

• Initializing a client using an initializer and sharing it across models (or whatever is preferred)
• Using API tokens other than the master key in the client
• Indexing and reindexing using database hooks
• Associating search results with ActiveRecord model items

[curquiza]

We activated the wiki again!
And we made it updatable by anyone. Feel free to contribute.

More clue:

Initializing a client using an initializer and sharing it across models (or whatever is preferred)

Rails integration README can help

Using API tokens other than the master key in the client

It's already in the README, it works the same than with API keys when initializing the client. Mayeb we could precise it in the README?

Indexing and reindexing using database hooks

Same, Rails related

Associating search results with ActiveRecord model items

Rails here