dan/ken:
* refactor test
ken/dan:
* wrote test for sources upvote count
* wrote migration to add column upvote_count to sources schema
dan/ken:
* refactor tests
* add validation tests
* add validations to source model
ken/dan:
* set default value of upvote_count equal to 0
dan/kenny:
* added upvote button
* pass in source.id as value of button
ken/dan:
* Attach event listener to upvote button
* Upon clicking upvote button, store source id
dan/ken:
* turn ApplicationController into a prototype
ken/dan:
* Guest can upvote sources
* Upvote is updated in database
* Ajaxified the upvote
Merge pull request #3 from danbender/upvote-sources

Upvote sources