Provide optional defaults

[matiasgarciaisaia]

It would be great to minimise the extension's required configuration.

We could default the extension to index every resource, and to have a minimal search-client.js file to include in Sprockets - it could, say, load jQuery-ui and turn any input#searchbox into an autocomplete that uses the index.

The ultimate goal is to make it dead-easy to try the gem, even if anyone will want to customise the integration.