Instructions to create initial "firebase" index

The export.paths in config.js file assumes that your Bonsai/ElasticSearch already has an index called "firebase", which it will search for various paths.  However, if you haven't manually added the "firebase" index, you will get thrown an "IndexMissingException[[firebase] missing]" error.  This step can be completed on the fresh Heroku install.
Move initial index setup to sub-instruction

Created a sub-instruction about creating the initial index, since you can actually deploy to Heroku successfully without the initial index -- you just can't run some of the demo code.
Merge pull request #9 from hsubu/patch-1

Instructions to create initial "firebase" index