Added 25000 entries from USDA Organics Database.

* added XL gem to parse a xlsx file
* added function to Certificate model to grab data from xlsx file
* Certificate model will need to be refactored - external source queries should go into service objects/classes
* added xlsx file to db directory
Resolving merge conflict. Merge branch 'feature/organics'
merge conflicts
Made database more robust

* added descriptions for certificates
* added index to companies name field
* moved database scraping tasks out of Certificate model and into a service object called ScraperService
* converted class methods into instance methods
Merge branch 'master' of https://github.com/fiddler-crabs-2014/tattle into chore/merge
Merge pull request #64 from tyleraadams/chore/merge

Chore/merge