Merge pull request #9 from drewda/master

Looks good. I'm not sure how I missed the pull request last week but it's merged now.
When document type is `delete`, there is no need to send `fields` attribute.

In fact, doing so will result in a warning like:

     "message" => "\"delete\" has unknown attribute(s): ['fields'] (near operation with index 1; document_id developmentdrewslzimaclocal67)"
readme: adding links to related gems
readme: adding examples of search requests #5
a small fix for commit 88e7e4eccd3af5ad3a6d377407a19d8a1077cd4c
Merge pull request #12 from drewda/readme-improvements

readme improvements
Merge pull request #11 from drewda/document-to-hash

When document type is `delete`, there is no need to send `fields` attribute